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  • Other Sources  (1,113)
  • FLUID MECHANICS AND HEAT TRANSFER  (1,113)
  • 1975-1979  (1,113)
  • 1
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    Motions of a liquid in a pulsating bulb with application to problems of blood flow (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: Potential flows may be utilized to represent motions produced in pulsating bulbs. While the initial bulb shape may be arbitrary, sequential shapes are related by affine transformations. Two components appear in the distribution of pressure, one dependent on the instantaneous velocity and the other on the acceleration. For flows with stationary streamlines the inertial impedance is that of a simple mass, and is proportional to the first moment of the actual mass of fluid contained within the bulb. Examples treated are: (1) Expanding and collapsing circular cylinders, and (2) elliptical cylinders in which the perimeter is held constant. The thickness of the pulsatile laminar boundary layer is found to be approximately on millimeter for conditions in the vicinity of the heart. Conditions for separation and turbulence differ from those in steady flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Ames Res. Center Collected Works of Robert T. Jones; p 957-965
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  • 2
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    Investigation B: Laminar confined coaxial entrance flow with heat generation (1975)
    In:  CASI
    Details
    Publication Date: 2009-11-16
    Description: The results of a parametric study on the entrance flow region in a gas core nuclear reactor are presented. The physical system is modeled as laminar confined, coaxial flow with heat generation in the inner fluid. The governing equations include the boundary layer approximations and the assumptions of only radial radiative transport of energy represented as an energy diffusion term. The Von Mises transformation and a zeta transformation are used to transform the equations into nonlinear nonhomogeneous convective-diffusion equations. A unique combination of forward and backward difference equations which yields accurate results at moderate computational times, is used in the numerical method. Results show that the rapidly accelerating, heat generating inner stream actually shrinks in radius as it expands axially.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Turbulence Coefficients and Stability Studies for the Coaxial Flow or Dissimiliar Fluids; 76 p
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  • 3
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    A numerical comparison with an exact solution for the transient response of a cylinder immersed in a fluid (1979)
    In:  CASI
    Details
    Publication Date: 2006-07-02
    Description: The transient response of an elastic cylindrical shell immersed in an acoustic media that is engulfed by a plane wave is determined numerically. The method applies to the USA-STAGS code which utilizes the finite element method for the structural analysis and the doubly asymptotic approximation for the fluid-structure interaction. The calculations are compared to an exact analysis for two separate loading cases: a plane step wave and an exponentially decaying plane wave.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., Pt. 3; p 23-28
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  • 4
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    Application of fluidics to new control components (1978)
    In:  CASI
    Details
    Publication Date: 2006-03-02
    Description: The inherent tolerance for nuclear radiation makes fluidic devices candidates for nuclear rocket control systems. Also, they are being considered for supersonic jet engine inlet control because of their high temperature and vibration tolerance. Three new control components being considered for these applications are described. A fluidic circuit to control a pneumatic stepping motor for nuclear rocket control drum actuation is discussed. An all-fluidic sensor being developed for determining the position of the normal shock in the inlet of a supersonic jet engine is outlined. A new vortex valve configuration is developed to prevent supersonic jet engine inlet unstarts by regulating bypass flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA, Washington Fourth Inter-Center Control Systems Conf.; p 365-386
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  • 5
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    Flow phenomena peculiar to calculation of compressible turbulent boundary layers (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Calculation procedures for compressible turbulent boundary layers were based upon techniques, modeling constants, etc., developed originally for the low speed case. Significant differences and new or altered physics which occur in the compressible case were considered, as compared with the low speed situation. Possible pitfalls and sources of inaccuracy in the calculations were indicated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 9-46
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  • 6
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    Surface-tension-induced convection experiment MA-041 (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: In the absence of gravity, stirring in a liquid is suppressed because of density differences caused by thermal or compositional gradients. However, other mechanisms resulting in natural convection in a microgravity environment exist. One of the most important mechanisms for liquid metals is surface tension driven convection, which becomes predominant in the low gravity environment. In this case, surface tension differences caused by compositional or temperature gradients have been demonstrated to cause stirring in liquids during experiments performed onboard Skylab. Compositional gradients were created by adding a soap solution to a large water globule, which caused vigorous fluid motion for some moments after the addition.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lyndon B. Johnson Space Center Apollo-Soyuz Test Project; 11 p
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  • 7
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    Summary of calculation procedures for nonsimilar two- and three-dimensional compressible turbulent boundary layers (finite difference, finite element and weighted residual methods), appendix (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: This numerical prediction summary indicates the wide variety of such procedures which are available. Most procedures have detailed user manuals, and in many cases the codes are available. Many of the special effects treated by various methods (such as nonequilibrium or equilibrium chemistry, transition, roughness etc.) are indicated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 69-78
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  • 8
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    Calculation of three-dimensional compressible turbulent boundary layers (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: From comparisons of high speed data with low speed closure procedures using variable mean density, there does not appear to be any appreciable influence of compressibility upon turbulent shear stress modeling in compressible turbulent boundary layers, even for extreme cases such as Mach 14 to 20 with a change in density across the layer of up to a factor of 100. Other evidence of apparent lack of compressibility caused new physics which may alter the shear stress for the compressible boundary layer cases including: (1) fluctuation Mach number was generally less than 1; (2) the shear stress distribution through the boundary layer was not a function of Mach number for zero pressure gradient flows; (3) the Morkovin hypothesis was valid up to Mach 5 (based on fluctuation data); (4) profile N power was not a function of Mach number, at least up to Mach 10; and (5) the nondimensional burst period was approximately the same as that for low speed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 47-68
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  • 9
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    Equations and closure methods (1977)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Basic differential equations governing compressible turbulent boundary layer flow are reviewed, including conservation of mass and energy, momentum equations derived from Navier-Stokes equations, and equations of state. Closure procedures were broken down into: (1) simple or zeroth-order methods, (2) first-order or mean field closure methods, and (3) second-order or mean turbulence field methods.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 6-8
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  • 10
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    Science demonstrations (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Three demonstrations of scientific concepts concerning liquids were performed during the Apollo-Soyuz Test Project mission. Chemical foaming, spreading of liquids, and capillary wicking were the subjects of each demonstration photographed in space. The results clearly illustrated the basic principles, and films suitable for educational uses are now available from the first author.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Apollo-Soyuz Test Project; 9 p
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  • 11
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    Heat pipes in space: A NASA summary (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Experiences derived from the development, integration, and flight of NASA spacecraft and sounding rockets are presented. They include the International Heat Pipe Experiment, OAO 3, and ATS-6. Typical flight data are presented to show the performance.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA Heat Pipes; p 647-653
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  • 12
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    Empirical correlations for heat transfer and flow friction characteristics of rectangular offset-fin plate-fin heat exchangers (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 13
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    Inviscid interpenetration of two streams with unequal total pressures (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A theory is proposed for analyzing the inviscid interpretation of two streams in the case when the difference in total pressure between the streams is relatively small. A stream is considered which discharges from a nozzle or reservoir into a partially moving and partially stationary environment in such a way that the flows leave the solid boundaries in a tangential direction where the two streams first interact. The problem is solved by expanding in a small parameter related to the difference in total pressure between the streams, the zeroth-order solution is obtained by classical methods, and a technique similar to that employed in thin-airfoil theory is used to transfer the first-order boundary conditions to the zeroth-order boundary. A procedure is developed to transform the problem into one that can be solved by standard techniques of the theory of sectionally analytic functions. Solutions are obtained for flows with and without free streamlines, and the general theory is applied to several specific flow configurations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 70; Aug. 12
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  • 14
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    Radiation exchange for a system with partially transmitting wall (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An approach is presented for applying the net radiation method developed by Siegel and Howell (1972) and Sparrow and Cess (1966) to systems involving opaque and partially transmitting walls. The results obtained from the basic equations for various values of plate emissivities and temperatures are presented in graphs. Attention is given to the window temperature relative to the temperature of the hot wall and the heat transferred relative to that transferred without the window.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Letters in Heat and Mass Transfer; 2; Mar
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  • 15
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    Derivation and application of the reciprocity relations for radiative transfer with internal illumination (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A Green's function formulation is used to derive basic reciprocity relations for planar radiative transfer in a general medium with internal illumination. Reciprocity (or functional symmetry) allows an explicit and generalized development of the equivalence between source and probability functions. Assuming similar symmetry in three-dimensional space, a general relationship is derived between planar-source intensity and point-source total directional energy. These quantities are expressed in terms of standard (universal) functions associated with the planar medium, while all results are derived from the differential equation of radiative transfer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer; 15; Sept
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  • 16
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    Radiation from an array of longitudinal fins of triangular profile (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Radiation from an array of longitudinal fins of triangular profile is analyzed, including fin-to-fin and fin-to-base interactions. The effect of base cylinder radiation and the fin-base radiative interaction is found to be significant for fin width/tube radius ratios less than 8. Results presented may be used to optimize the design of a fin array with respect to weight.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; May 1975
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  • 17
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    Comment on 'subsonic and supersonic boundary-layer flow past a wavy wall' (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; Apr. 197
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  • 18
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    Characteristics of the unsteady motion on transversely sheared mean flows (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An explicit representation for the unsteady motion on a transversely sheared mean flow is obtained which corresponds to the gustline motion on a uniform mean flow. The important features of this motion are discussed. It is shown that its velocity, pressure and vorticity are all induced by a certain disturbance field that is a linear combination of the vorticity and particle-displacement fields and is everywhere frozen in the mean flow. The general ideas are illustrated by considering the scattering of a gust by a half-plane embedded in a shear flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 84; Jan. 30
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  • 19
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    Three-dimensional low Reynolds number flows with a free surface (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The two-dimensional leveling problem (Degani, Gutfinger, 1976) is extended to three dimensions in the case where the flow Re number is very low and attention is paid to the free surface boundary condition with surface tension effects included. The no-slip boundary condition on the wall is observed. The numerical solution falls back on the Marker and Cell (MAC) method (Harlow and Welch, 1965) with the computation region divided into a finite number of stationary rectangular cells (or boxes in the 3-D case) and fluid flow traverses the cells (or boxes).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics; 24; May 1977
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  • 20
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    Derivation of the Navier-Stokes equation (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The proposed approach to the derivation of the Navier-Stokes equation is thought to be more plausible and easier to understand than other derivations that can be found in works on fluid mechanics. The tensor character of the stress is central to the derivation. In particular, a linear relation between stress and strain rate is assumed only for the shear, rather than for the full stress tensor as is done in most other derivations. An assumption for the shear is naturally simpler and easier to verify experimentally. The use of tensor analysis is shown to greatly simplify the derivation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: American Journal of Physics; 44; Nov. 197
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  • 21
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    Six-beam models in radiative transfer theory (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A critical analysis is given of the applicability of six-beam models to radiative transfer in particulate materials. The method of introducing transverse scattering in these models is shown to cause fundamental difficulties in the case of physically plausible phase functions; in particular, the effective absorptivity is abnormally large and thus results in incorrect reflectances and transmittances. Six-beam calculations for several media are compared with accurate solutions, with Chu-Churchill two-beam results, and with a simple modification to the Eddington approximation, the last being generally superior over a wide range of conditions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Applied Optics; 15; Dec. 197
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  • 22
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    Influence of heat transfer on the stability of parallel flow between concentric cylinders (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The stability of the parallel flow of water between concentric cylinders at different temperatures is investigated for infinitesimal velocity and pressure disturbances. Primary interest is in the effect of heat transfer and the radius ratio a/b on the critical point of the neutral stability curve. The results indicate a strong dependence of the critical eigenvalues on both the heat transfer and the radius ratio. The critical Reynolds number of the nonisothermal flow appears to approach a finite value as the inner radius approaches zero (pipe flow) by showing an inflection point on the curve of critical Reynolds number vs a/b.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 19; Nov. 197
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  • 23
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    Comparison of theory and experiment for homogeneous turbulence with shear (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Solutions for uniformly-sheared turbulence, in which the interaction of the turbulence with the mean shear dominates the turbulent self-interaction, are compared with experiment. An anisotropic spectral tensor, which appears general enough to represent the initial experimental turbulence, is used for the initial condition in the calculations. The evolution of one-point turbulence components and microscales, as well as two-point velocity correlations, are considered. In most cases the agreement with experiment is good. The theory correctly predicts the presence of a negative region for two-point longitudinal-velocity correlations only for point separations in the direction normal to the flow and the mean gradient.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 18; Oct. 197
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  • 24
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    Influence of probe geometry on pitot-probe displacement in supersonic turbulent flow (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An experiment was conducted to determine the varying effects of six different probe-tip and support-shaft configurations on pitot tube displacement. The study was stimulated by discrepancies between supersonic wind-tunnel tests conducted by Wilson and Young (1949) and Allen (1972). Wilson (1973) had concluded that these discrepancies were caused by differences in probe geometry. It is shown that in fact, no major differences in profiles of streamwise velocity over streamwise velocity at boundary-layer edge vs normal coordinate over boundary-layer total thickness result from geometry. The true cause of the discrepancies, however, remains to be discovered.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; July 197
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  • 25
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    Flow rates for sharp-edged orifices (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Two charts are proposed for calculating the flow coefficient and the area correction factor used in the equation for the flow rate through a sharp-edged orifice. The proposed charts account for variations in the discharge coefficient of sharp-edged orifices and can be used with any pressure ratio for both subcritical and supercritical flow conditions. They can also be used for any gas by using the appropriate gas constant and ratio of specific heats. The application of the charts is illustrated by examples.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Machine Design; 47; June 12
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  • 26
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    Radiative equilibrium in a rectangular enclosure bounded by gray walls (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Two-dimensional temperature and heat-flux distributions are calculated for an absorbing-emitting gray medium at radiative equilibrium in a rectangular enclosure. The bounding walls are gray and diffuse with arbitrary surface-temperature distributions, and heat generation may take place inside the medium. As a first approximation, the problem is solved for optically thick systems (differential approximation). These results are subsequently improved by the introduction of a number of geometrical parameters to yield good accuracy for all optical thicknesses. As examples, two cases are discussed in detail: (1) uniform heat generation in a black enclosure, and (2) an enclosure with one gray surface at constant temperature. Comparison with some numerical solutions generated by Hottel's /Hottel and Cohen (1958) and Einstein (1963)/ zonal method shows excellent agreement.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer; 15; June 197
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  • 27
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    Investigation A: Numerical solutions of driven vortices of binary fluid in a cylindrical geometry (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The steady state laminar motion of a viscous, incompressible and binary fluid is studied for a rotating flow in a cylindrical geometry. The mathematical model employed is a cold flow simulation of the fluid mechanics of the light-bulb concept of the gaseous core nuclear engine. A numerical treatment is developed for the rotating flow which includes a description of the nuclear fuel addition. The problem is formulated with the complete Navier-Stokes equations in order to show the interaction between the fuel addition, the main flow, and the boundary layer flow in an accurate manner. The results presented show holdup of the nuclear fuel for the case of steady fuel addition.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Turbulence Coefficients and Stability Studies for the Coaxial flow or Dissimiliar Fluids; 146 p
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  • 28
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    Supersonic Mixing and Combustion in Parallel Injection Flow Fields (1975)
    In:  CASI
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    Publication Date: 2011-01-13
    Description: Adequate prediction techniques for supersonic, mixing, reacting flows are of great importance in the design and performance analysis of supersonic combustion ramjet (scramjet) engines. Analytical programs for parallel injection flow fields with chemical reaction and turbulent mixing are now available for both single and multiple-jet flows. The application of these analyses to simple flow geometries is discussed, and comparisons also are made with data on the more complex case of multiple-jet, reacting flows. A review is given of Langley investigations of parallel injection flow fields. Among these are single-jet studies of nonreacting, turbulent mixing (H2 in air and H2 in N2), and of reacting turbulent mixing (H2 in air) with both single and multiple jets. Implications of the results of the studies for scramjet fuel injector design are discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Anal. and Numerical Methods for Invest. of Flow Fields with Chem. Reactions, Especially Related to Combust.; 8 p
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  • 29
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    Kinetic theory analysis of rarefied gas flow through finite length slots (1977)
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    Publication Date: 2011-08-17
    Description: A kinetic-theory analysis is made of the flow of a rarefied monatomic gas through a two-dimensional slot connecting two reservoirs. Numerical solutions are obtained by the moment and discrete-ordinate methods. The former method portrays the transition-regime characteristics well but has limitations in the free-molecule regime. The latter method gives accurate results in the free-molecule and slip regimes and bolsters confidence in the accuracy of the transition-regime results. The numerical solution for the mass flux through the slot agrees well with an approximate analytical solution of the moment equations for length-to-width ratios from 6 to 0.5, pressure ratios from 0.8 to 0.1, and Knudsen numbers from 5 to 0.5.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 20; June 197
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  • 30
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    Numerical computation of transient coaxial entry tube flows (1976)
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    Publication Date: 2011-08-17
    Description: A numerical program was developed to compute transient laminar flows in two dimensions including multicomponent mixing and chemical reaction. The program can compute both incompressible flows and compressible flows at all speeds, and it is applied to describe transient and steady state solutions for low subsonic, coaxial entry, tue flows. Single component, nonreacting flows comprise most of the solutions, but one steady state solution is presented for trace concentration constituents engaging in a second order reaction. Numerical stability was obtained by adding at each calculation point a correction for numerical diffusion errors caused by truncation of the Taylor series used to finite difference the conservation equations. Transient computations were made for fluids initially at rest, then subjected to step velocity inputs that were uniform across each region of the entry plane and were held constant throughout the computation period. For center tube to annulus velocity ratios of 0.5 and 2.0, the bulk fluid in the tube initially moved in plug flow, but strong radial flows developed near the injection plane which moved the fluid into the high shear region between the jets and away from the tube wall.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computers and Fluids; 4; Dec. 197
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  • 31
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    Transport processes in boiling and two-phase systems, including near-critical fluids (1976)
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    Publication Date: 2011-08-17
    Description: Aspects of pool boiling are considered, taking into account nucleate boiling, the nucleate boiling mechanism, film boiling, and the transition between nucleate and film boiling. The characteristics of two-phase flow are also investigated, giving attention to two-phase flow parameters and equations, the flow pattern in two-phase flow, the pressure drop in two-phase flow, heat transfer in two-phase flow, two-phase flow dynamics, the boiling crisis in two-phase flow, the critical flow rate, the propagation of the pressure pulse and the sonic velocity in two-phase media, instrumentation for two-phase flow, and geometry and field effects on boiling and two-phase flow. Near-critical fluids are also considered.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 32
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    Effects of atomic oxygen on graphite ablation (1976)
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    Publication Date: 2011-08-17
    Description: It is shown that a previously derived semiempirical equation for describing observed ablation rates of isotropic graphites cannot be applied to low-density flows containing dissociated oxygen. Experimentally determined reaction probabilities of isotropic graphites to molecular and atomic oxygen are used to calculate heat-transfer rates and stagnation-point ablation rates for typical conditions. Integrated mass losses are computed for a group of flight trajectories which start from geosynchronous orbit and enter earth's atmosphere in a skipping motion following near-elliptic decaying orbits. A comparison of the results with those obtained by the equation under question shows excellent agreement for steep trajectories, but large discrepancies for shallow trajectories. The differences are attributed to surface oxidation by atomic oxygen.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 14; Nov. 197
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    Nonlinear effects for the Taylor column for a hemisphere (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: When a flow is forced past an obstacle in a rapidly rotating fluid, a Taylor column forms. This is defined by a set of vertical detached shear layers circumscribing the obstacle which provide the smooth transition from an external inviscid potential flow to a stagnant core above the obstacle. For a hemispherical object, the main adjustment takes place in an external E to the 1/4 power layer and an internal E to the 2/7 power layer; here, the nonlinear flow in these layers is investigated. The problem in the E to the 1/4 power layer is identical to a problem occurring in magnetohydrodynamic flow; in addition, some features of the magnetohydrodynamic problem have been resolved. Numerical solutions are obtained for the steady nonlinear external E to the 1/4 power layer flow up to the point where unsteady flow separation from the Taylor column is imminent. The response of the internal E to the 2/7 power layer to the flow in the E to the 1/4 power layer is calculated, and the results suggest that the internal shear layer is unlikely to play any significant role in the separation process
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 19; Nov. 197
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    The International Heat Pipe Experiment (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: On October 4, 1974, the International Heat Pipe Experiment was launched aboard a Black Brant sounding rocket from White Sands, New Mexico. The flight provided six min of near zero gravity during which a total of ten separate heat pipe experiments was performed. The fifteen heat pipes tested represent some of the latest American and European technology. This flight provided the first reported zero gravity data on cryogenic and flat plate vapor chamber heat pipes. Additionally, valuable design and engineering data were obtained on several other heat pipe configurations. The payload and several of its experiments are discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA Heat Pipes, Vol. 2; p 815-837
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    Gasdynamics and shock dynamics of weak shock waves (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Experiments in weak-shock dynamics were conducted using a 17-in. diameter shock tube. Weak shocks were generated in air by a compressed nitrogen driver gas; the incident shock waves were brought to a focus by reflecting them from concave cylindrical reflectors at the endwall of the tube. It was found that the behavior of a shock discontinuity at a focus is determined by nonlinear gasdynamic processes. Consideration is also given to nonlinear resonance phenomena, i.e., phenomena associated with oscillatory motion in ducts, with amplitude so large that weak shocks occur. Attention is given to nonlinear resonance in open and closed tubes and to thermal and relaxation effects.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Drop dynamics in space (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Drop experiments proposed for Spacelab are discussed and an acoustic chamber utilizing the torques and forces produced by acoustic waves excited within the chamber is described. Its operation and how it is being tested for experiments is discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA Mater. Sci. in Space; p 405-419
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  • 37
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    The laminar compressible boundary layer on a rotating sphere with heat transfer (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The paper presents a theoretical analysis of the thermal boundary layer induced by an isothermal sphere rotating in an otherwise quiescent fluid. The boundary layer is considered to be laminar and compressible, and the effects of buoyancy and viscous dissipation on torque, heat transfer, and the position of the ideal jet (the plane of impingement of the boundary layer from the Northern and Southern Hemispheres) are taken into account.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Parametric performance of circumferentially grooved heat pipes with homogeneous and graded-porosity slab wicks at cryogenic temperatures (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A recently developed, potentially high-performance nonarterial wick was extensively tested. This slab wick has an axially varying porosity which can be tailored to match the local stress imposed on the wick. The purpose of the tests was to establish the usefulness of the graded-porosity slab wick at cryogenic temperatures between 110 and 260 K, with methane and ethane as working fluids. For comparison, a homogeneous (i.e., uniform porosity) slab wick was also tested. The tests included: maximum heat pipe performance as a function of fluid inventory, maximum performance as a function of operating temperature, maximum performance as a function of evaporator elevation, and influence of slab wick orientation on performance. The experimental data were compared with theoretical predictions obtained with the GRADE computer program.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA Heat Pipes; p 63-76
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  • 39
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    Higher order accurate difference solutions of fluid mechanics problems by a compact differencing technique (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A general fourth order differencing scheme is developed and applied to three viscous test problems to verify the accuracy and applicability of the technique. The procedure is atypical since only three nodes are necessary to obtain the desired fourth order accuracy. This is accomplished by a differencing technique which considers the function and all necessary derivatives as unknowns. The relations for these derivatives yield simple tridiagonal equations which can be easily solved. Comparisons of the fourth order results with those computed using second order methods are presented for the test problems and clearly indicate that the accuracy achieved by these fourth order computations is always significantly better than current second order procedures.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics; 19; Sept
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  • 40
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    Relaxation methods in fluid mechanics (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The present work considers the iterative solution of a coupled set of difference equations and examines methods that carry successive approximates to a state that is invariant with further iteration and independent of the initial guess. Methods are studied with regard to their efficiency and economy of computer resources. The basic principles of classical relaxation are set forth, with attention confined to linear elliptic equations. This discussion involves the evaluation of the spectral radius that is the magnitude of the eigenvalue with largest modulus. The subject of relaxation is then related to the study of ordinary differential equations and hyperbolic partial differential equations. Problems that occur when linearly dependent eigenvectors appear in the relaxation matrix are discussed, leading to multiply connected eigenvalues in the Jordan canonical form. Finally, a brief survey of relaxation methods used in aerodynamics is given.
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    A BBGKY framework for fluid turbulence (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A framework is presented for a systematic kinetic theory of turbulence originating from the Liouville equation for the Fourier coefficients of fluid variables. The real and imaginary parts of these Fourier coefficients play the role that particle coordinates (positions and momenta) play in the BBGKY theory. The basic relations of the problem are the incompressible Navier-Stokes equations in two dimensions with zero viscosity, with the probability distributions of Fourier coefficients rather than moments being the basic variables of the theory. A kinetic equation is derived and shown to possess a number of requirements that any reasonable kinetic equation must have: conservation laws, positive-definite spectral densities, and an H-theorem. The major lack in the theory is any reliable information on the relaxation predicted by the complicated linear operator H. Closure of the hierarchy is achieved by the hypothesis that the five-coefficient correlation function is negligible. Problems associated with inclusion of viscosity and external driving forces are discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 19; June 197
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  • 42
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    Critical issues in viscous flow computations (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: In developing computer programs to numerically solve the Navier-Stokes equations, the purpose of the computation must be clearly kept in mind. In the Air Force, the purpose is to provide design information on non-linear aerodynamic phenomenon for aircraft that perform throughout the flight corridor. This translates into the requirement for a computer program which can solve the time averaged compressible Navier-Stokes equations (with a turbulence model) in three dimensions for generalized geometries. The intended application of the results then controls the priorities in addressing critical issues. Recurrent problem areas encountered in the study of viscous flow include: (1) grid generation for arbitrary geometry; (2) numerical difficulties; (3) turbulence models; (4) accuracy and efficiency; and (5) smearing of discontinuities.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Ames Res. Center Future Computer Requirements for Computational Aerodynamics; p 168-175
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    Computational requirements for three-dimensional flows (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The computational requirements needed for predicting steady viscous flow over complex configurations are considered. The desired predictions must be made at reasonable expense, require a reasonable amount of storage space, and result in solutions that are sufficiently accurate. The data needed to estimate the cost of Navier-Stokes solutions is not available; therefore, experience with the solution of the three-dimensional boundary layers equations are used to illustrate the needed information and what can be expected for the Navier-Stokes solutions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Ames Res. Center Future Computer Requirements for Computational Aerodynamics; p 145-153
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    A dual assault upon turbulence (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: All known calculation methods incorporate some sort of turbulence model to reduce the infinite hierarchy of equations, under Reynolds' averaging, to a finite set. All such models suffer from a certain ad hoc nature. A dual structure model was developed wherein the turbulence field is, somewhat arbitrarily, decomposed into large eddies which presumably are dominant contributors to the Reynolds' stress and small eddies which feed on the large eddies as these, in turn feed upon the average flow to gain their energy. These concepts have been developed into a dual approach, one extractive and the other predictive as outlined below.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Ames Res. Center Future Computer Requirements for Computational Aerodynamics; p 260-266
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  • 45
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    Effect of compliant wall motion on turbulent boundary layers (1977)
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    Publication Date: 2011-08-17
    Description: A critical analysis of available compliant wall data which indicated drag reduction under turbulent boundary layers is presented. Detailed structural dynamic calculations suggest that the surfaces responded in a resonant, rather than a compliant, manner. Alternate explanations are given for drag reductions observed in two classes of experiments: (1) flexible pipe flows and (2) water-backed membranes in air. Analysis indicates that the wall motion for the remaining data is typified by short wavelengths in agreement with the requirements of a possible compliant wall drag reduction mechanism recently suggested by Langley.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    An implicit-iterative solution of the heat conduction equation with a radiation boundary condition (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: For the problem of predicting one-dimensional heat transfer between conducting and radiating mediums by an implicit finite difference method, four different formulations were used to approximate the surface radiation boundary condition while retaining an implicit formulation for the interior temperature nodes. These formulations are an explicit boundary condition, a linearized boundary condition, an iterative boundary condition, and a semi-iterative boundary method. The results of these methods in predicting surface temperature on the space shuttle orbiter thermal protection system model under a variety of heating rates were compared. The iterative technique caused the surface temperature to be bounded at each step. While the linearized and explicit methods were generally more efficient, the iterative and semi-iterative techniques provided a realistic surface temperature response without requiring step size control techniques.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Engineering; 11; 10, 1; 1977
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  • 47
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    Turbulence stress measurements in a nonadiabatic hypersonic boundary layer (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Turbulent shear stress and direct turbulent total heat-flux measurements have been made across a nonadiabatic, zero pressure gradient, hypersonic boundary layer by using specially designed hot-wire probes free of strain-gauging and wire oscillation. Heat-flux measurements were in reasonably good agreement with values obtained by integrating the energy equation using measured profiles of velocity and temperature. The shear-stress values deduced from the measurements, by assuming zero correlation of velocity and pressure fluctuations, were lower than the values obtained by integrating the momentum equation. Statistical properties of the cross-correlations are similar to corresponding incompressible measurements at approximately the same momentum-thickness Reynolds number.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; Dec. 197
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  • 48
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    Shock interference peak heating measurements using phase change coatings (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The phase change coating technique is used to obtain peak heating measurements in shock interference flow regions with high surface shear and heating. This technique provides heat transfer coefficients which are determined by measuring the time for a point on the surface to reach the phase change temperature of the thin fusible coating. Measurements were conducted on a 5.08-cm diameter hemisphere-cylinder made of silica based epoxy at Mach 6 for free stream Reynolds numbers of 3.3 to 25.6 million per meter. A sketch of the shock interference pattern produced by a flat plate shock generator is included. Heating data obtained on a 5.08-cm diameter stainless steel hemispherical model instrumented with thermocouples is presented for the purpose of comparing the phase change technique with the thermocouple-calorimeter technique.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Spacecraft and Rockets; 13; Jan. 197
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  • 49
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    Laminar free convection from a vertical cone with uniform surface heat flux (1976)
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    Publication Date: 2011-08-16
    Description: The laminar free convection flow from a right circular cone with prescribed uniform wall flux condition is studied. The governing boundary-layer equations are analyzed by the technique of similarity transformation. Numerical solutions to the transformed equations are given for Prandtl numbers 0.72, 1, 2, 4, 6, 8, 10, and 100. Expressions for both wall temperature distribution and wall skin friction distribution at Prandtl number tending to infinity are also presented.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Letters in Heat and Mass Transfer; 3; Jan
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  • 50
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    Computing viscous flows (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Although the goals and techniques of computational aerodynamics and computational fluid dynamics differ, advancement in the physical and mathematical aspects of the latter are required for progress in aerodynamic computation. The most attractive approach is the use of hybrid methods where both the equations treated and the solution algorithms reflect the local character of the flow. A working general turbulence model that is only peripherally related to the availability of large fast computers would provide a significant breakthrough in computational aerodynamics. There is no unanimity of opinion as to what may be the optimum algorithm or family of algorithms in the next decade. While it is premature to develop an optimum processor, such a machine dedicated to study the structure of solutions to the three-dimensional time-dependent Navier-Stokes equations and to the computability of turbulence would be very valuable.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Future Computer Requirements for Computational Aerodynamics; p 209-220
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    Viscous flow simulation requirements (1978)
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    Publication Date: 2011-08-17
    Description: Although significant advances have been made in the simulation of two-dimensional compressible laminar viscous flows by numerically solving the compressible Navier-Stokes (N.S.) equations, problem areas still remain to be solved before viscous flows requiring solution of the compressible N.S. equations can be efficiently and accurately simulated for flows of aerodynamic interest. These problem areas include turbulence (three-dimensional character), complex geometry, flow unsteadiness, placement of artificial boundaries relative to solid boundaries, specification of boundary conditions, and large flow gradients near surfaces and in the vicinity of shock waves for supersonic flows.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Ames Res. Center Future Computer Requirements for Computational Aerodynamics; p 176-208
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    Computational Fluid Dynamics (CFD): Future role and requirements as viewed by an applied aerodynamicist (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The problem of designing the wing-fuselage configuration of an advanced transonic commercial airliner and the optimization of a supercruiser fighter are sketched, pointing out the essential fluid mechanical phenomena that play an important role. Such problems suggest that for a numerical method to be useful, it must be able to treat highly three dimensional turbulent separations, flows with jet engine exhausts, and complex vehicle configurations. Weaknesses of the two principal tools of the aerodynamicist, the wind tunnel and the computer, suggest a complementing combined use of these tools, which is illustrated by the case of the transonic wing-fuselage design. The anticipated difficulties in developing an adequate turbulent transport model suggest that such an approach may have to suffice for an extended period. On a longer term, experimentation of turbulent transport in meaningful cases must be intensified to provide a data base for both modeling and theory validation purposes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Ames Res. Center Future Computer Requirements for Computational Aerodynamics; p 132-142
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    Numerical turbulence modeling (1977)
    In:  CASI
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    Publication Date: 2012-05-19
    Description: The underlying bases and developments in two techniques of detailed turbulence modeling are described where the flow is treated in the Eulerian sense, and one technique where the Lagrangian motions of vortices are followed. First, a technique is described for solving the single-point statistically averaged conservation equations. The Reynolds stresses that appear in these equations are evaluated by solving supplemental differential equations which contain terms that are modeled. A sequence of increasingly complex, but also increasingly general, modeling equations is described and computations based on these equations are compared with experimental data. The hierarchy of models described terminates with equations for the individual components of the Reynolds stress tensor. The second Eulerian technique approach to turbulence modeling is the direct numerical simulation of turbulent fields. In this approach, all three dimensional eddies between a predetermined range of sizes are computed in time within a specified volume of flow. Present day computers require a tradeoff between the size of the volume that can be considered and the degree of resolution of the turbulent eddies. Techniques of modeling the smallest eddies are described that permit enlarging the volume, or Reynolds number, that can be considered.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Computational Fluid Dyn.; 37 p
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    A numerical study of capillary stability in a circular cylindrical container with a concave spheroidal bottom (1978)
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    Publication Date: 2011-08-17
    Description: The paper describes a theoretical investigation of the stability under gravitational and surface forces of a liquid in a circular cylindrical container with a concave spheroidal bottom for the case in which the volume of the liquid is sufficiently small so that the bottom is not covered completely. The gravitational field is assumed to be directed along the symmetry axis of the container, and for a specific container shape the critical Bond number is calculated as a function of liquid volume for contact angles of gamma = 0, 1, 2, and 4 deg. For gamma = 0 deg, some critical equilibrium configurations and corresponding perturbation modes are presented.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computer Methods in Applied Mechanics and Engineering; 16; Dec. 197
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    Numerical solution of compressible viscous flows (1979)
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    Publication Date: 2011-08-17
    Description: The presented review is concerned with the problem of calculating compressible viscous flows. Basic numerical considerations and problems associated with calculating viscous flows are examined and current numerical approaches toward the solution of the Navier-Stokes equations are discussed. It is pointed out that the numerical solution of the full time-dependent equations for turbulent flow is not practical with present computers. Therefore, turbulence effects must be accounted for by modeling. Developments related to turbulence modeling are described. In connection with a discussion of numerical methods for solving viscous flow equations, attention is given to numerical domains of dependence of typical explicit and implicit methods, the diffusion problem, the convection-diffusion problem, and the split-hybrid method.
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    A comparison of the Method of Lines to finite difference techniques in solving time-dependent partial differential equations (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Steady state solutions to two time dependent partial differential systems have been obtained by the Method of Lines (MOL) and compared to those obtained by efficient standard finite difference methods: (1) Burger's equation over a finite space domain by a forward time central space explicit method, and (2) the stream function - vorticity form of viscous incompressible fluid flow in a square cavity by an alternating direction implicit (ADI) method. The standard techniques were far more computationally efficient when applicable. In the second example, converged solutions at very high Reynolds numbers were obtained by MOL, whereas solution by ADI was either unattainable or impractical. With regard to 'set up' time, solution by MOL is an attractive alternative to techniques with complicated algorithms, as much of the programming difficulty is eliminated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computers and Fluids; 6; June 197
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    Experimental temperature distribution and heat load characteristics of rotating heat pipes (1978)
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    Publication Date: 2011-08-17
    Description: Experimental results show conclusively that the presence of a small quantity of a noncondensable gas (NCG) mixed with the working fluid has a considerable effect on the condensation process in a rotating heat pipe. The temperature distribution in the condenser shows the blanketing effect of the NCG and the ratio of the molecular weight of the working fluid to that of the NCG has a very definite effect on the shape of this distribution. Some of the effects are quite similar to the well-established data on stationary heat pipes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer; 21; Feb. 197
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    The effect of external boundary conditions on condensation heat transfer in rotating heat pipes (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Experimental evidence shows the importance of external boundary conditions on the overall performance of a rotating heat pipe condenser. Data are presented for the boundary conditions of constant heat flux and constant wall temperature for rotating heat pipes containing either pure vapor or a mixture of vapor and noncondensable gas as working fluid.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer; 22; Aug. 197
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  • 59
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    Turbulence generated by the interaction of entropy fluctuations with non-uniform mean flows (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The turbulence generated by random entropy fluctuations in an accelerating stream is analyzed. The results are obtained by using rapid distortion theory together with a high frequency solution of a previously developed wave equation that governs the small-amplitude unsteady vortical and entropic motion on steady potential flows (Goldstein, 1978). Simple results are obtained for the case of symmetric contraction, expansion or combination of the two. It is shown that the energy of the entropy-generated turbulence increases more rapidly with the contraction ratio of a subsonic flow than that of any imposed upstream turbulence. This result indicates that the entropy-generated turbulence may be more significant than the hydrodynamically generated turbulence in the turbine stages of aircraft engines.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 93; July 26
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    Transient ablation of Teflon in intense radiative and convective environments (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: On the basis of this investigation of the high-temperature behavior of polytetrafluoroethylene (PTFE), the transient one-dimensional ablation of PTFE has been developed by taking into account the optical transmittance of both the amorphous zone and the crystalline zone of PTFE layer. Results show that although the exposed surface receded at an apparently steady state, both the internal temperature and the thickness of the gel layer increase continuously due to the internal absorption of radiation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 17; June 197
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    Scattering and distortion of the unsteady motion on transversely sheared mean flows (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: It is shown that the pressure and velocity fluctuations of the unsteady motion on a transversely sheared mean flow can be expressed entirely in terms of the derivatives of two potential functions. One of these is a convected quantity that can be specified as a boundary condition and is related to a transverse component of the upstream velocity field. The other can be determined by solving an inhomogeneous wave equation whose source term is also a convected quantity that can be specified as a boundary condition in any given problem. The general theory is used to study the interaction of an unsteady flow with a semi-infinite plate embedded in a shear layer. The acoustic field produced by this interaction is calculated in the limits of low and high frequency. The results are compared with experimental one-third octave sound pressure level radiation patterns. The agreement is found to be excellent, especially in the low frequency range, where the mean-flow and convective effects are shown to have a strong influence on the directivity of the sound.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 91; Apr. 27
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    Surface waves generated by shallow underwater explosions (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Surface water waves generated by surface and near surface point explosions are calculated. Taking the impulse distribution imparted at the water surface by the explosion as the overriding mechanism for transferring energy of the explosive to surface wave motion, the linearized theory of Kranzer and Keller is used to obtain the wave displacement in the far field. The impulse distribution is obtained by integrating the pressure wave over an appropriate time interval on a horizontal surface just beneath the undisturbed water surface. For surface explosions, a modified form of the similarity method first used by Collins and Holt is used to obtain the flow field. In the case of submerged explosions, the flow field is estimated by making necessary modifications to Sedov's similarity solution to account for the venting that accompanies the interaction of the leading (blast) wave with the ocean surface. Surface waves generated by a charge at six depths of placement (0.15 m, 0.30 m, 0.61 m, 0.91 m, 1.37 m, 3.05 m) are considered in addition to surface explosions. The results seem to support the existence of an upper critical depth phenomenon (of the type already established for chemical explosions) for point (nuclear) explosions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 21; Oct. 197
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  • 63
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    Navier-Stokes solutions using Stetter's method (1978)
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    Publication Date: 2011-08-17
    Description: Compressible Navier-Stokes equations for quasi-one-dimensional flow in a converging-diverging nozzle have been solved using Stetter's three-step predictor-corrector technique. Particular emphasis is given to the minimum iterative step feature for steady-state solutions. It is found that for the nonviscous-dominated case, Stetter's method attains the steady-state solution in the fewest steps when compared to four other currently used techniques.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 16; Sept
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  • 64
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    Prediction of outer layer mixing lengths in turbulent boundary layers (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Predictions of mixing length by Pletcher's (1976) method (using a two-layer eddy viscosity model for a turbulent boundary layer at low Reynolds numbers) are compared to some values derived from turbulent boundary-layer profiles by other authors. The model is incorporated into a finite-difference scheme, to accurately predict low Reynolds number skin friction in supersonic flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 15; Apr. 197
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  • 65
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    Hot-wire anemometry in transonic flow (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The use of hot-wire anemometry for obtaining fluctuating data in transonic flows has been evaluated. From hot-wire heat loss correlations based on previous transonic data, the sensitivity coefficients for velocity, density, and total temperature fluctuations have been calculated for a wide range of test conditions and sensor parameters. For sensor Reynolds number greater than 20 and high sensor overheat ratios, the velocity sensitivity remains independent of Mach number and equal to the density sensitivity. These conditions were verified by comparisons of predicted sensitivities with those from recent direct calibrations in transonic flows. Based on these results, techniques are presented to obtain meaningful measurements of fluctuating velocity, density, and Reynolds shear stress using hot-wire and hot-film anemometers. Example of these measurements are presented for two transonic boundary layers.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 15; Mar. 197
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  • 66
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    The influence of upstream conditions on flow reattachment lengths downstream of an abrupt circular channel expansion (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Biomechanics; 9; 1976
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  • 67
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    Steady accretion of a rotating fluid (1976)
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    Publication Date: 2011-08-16
    Description: The accretion of rotating gas on to a gravitating object is investigated by means of a perturbation to the spherically symmetrical flow. An expression is found for the correction to the accretion rate due to rotation of the gas in terms of the boundary conditions far from the object. In the case of accretion from a cloud with uniform angular velocity, the gas is accreted preferentially from a 'jet' near the axis of rotation. The angular-momentum distribution in the cloud can be altered by the propagation of inertia waves.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Astrophysical Journal; 208; Sept. 1
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  • 68
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    A block iterative finite element algorithm for numerical solution of the steady-state, compressible Navier-Stokes equations (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An iterative method for numerically solving the time independent Navier-Stokes equations for viscous compressible flows is presented. The method is based upon partial application of the Gauss-Seidel principle in block form to the systems of the nonlinear algebraic equations which arise in construction of finite element (Galerkin) models approximating solutions of fluid dynamic problems. The continuous cubic element on triangles is employed for function approximation. Computational results for a free shear flow at Re = 1000 indicate significant achievement of economy in iterative convergence rate over finite element and finite difference models which employ the customary time dependent equations and symptotic time marching procedure to steady solution. Numerical results are in excellent agreement with those obtained for the same test problem employing time marching finite element and finite difference solution techniques.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Engineering; 11; 12, 1; 1977
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  • 69
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    Condensation heat transfer in rotating heat pipes in the presence of a non-condensable gas (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An analysis of condensation problems in rotating heat pipes containing vapors with different concentrations of non-condensable gases is given. In situations such as this, temperature and concentration gradients are set up in the vapor-gas mixture. There is a transport of mass due to temperature gradients accompanied by an energy transport phenomena due to a concentration gradient. A Nusselt type analysis is not suited to this type of problem; however, a boundary layer type approach has successfully been used to analyze stationary condensation systems with non-condensable gases present. The present boundary layer analysis is presented for condensation processes on the inside of a rotating heat pipe in the presence of non-condensable gases.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Revue Roumaine des Sciences Techniques; vol. 22
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  • 70
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    Revised international representations for the viscosity of water and steam and new representations for the surface tension of water (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 71
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    The International Heat Pipe Experiment (1976)
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    Publication Date: 2011-08-16
    Description: The aims of the experiment are outlined. Flight experiments included in this program were provided by NASA, Goddard Space Flight Center, ESA (European Space Agency), the German Ministry of Technology, Hughes Aircraft Company and NASA, Ames Research Center.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA Heat Pipes; p 589-591
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  • 72
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    Performance characteristics of rotating wickless heat pipes (1976)
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    Publication Date: 2011-08-16
    Description: A theoretical model was derived for laminar film condensation on the inside of a rotating, truncated cone which includes the effects of vapor shear and vapor pressure drop. Results are compared to those of previous investigations. Experimental data are presented for rotational speeds of 700, 1,400, 2,100, and 2,800 rpm using water, ethyl alcohol, and Freon 113 as working fluids. Agreement between theory and experiment is within + or - 20 percent.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ESA Heat Pipes; p 281-291
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  • 73
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    Experimental verification of turbulent skin friction reduction with compliant walls (1975)
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    Publication Date: 2011-08-16
    Description: Preliminary compliant wall skin friction test results obtained in a low-turbulence pressure tunnel are reported. Compliant surface skins consisted of 0.0025 cm thick mylar, stretched under tension and area-bonded or longitudinally strip-bonded with silicone rubber adhesive to polyurethane foam. Mean velocity and fluctuating survey data were obtained with a single slanted hot wire. Mean velocity profiles for the area-bonded mylar surface skins indicated up to a 20% reduction in boundary-layer thickness (and lower momentum thickness) over rigid surfaces. This reduction in boundary-layer thickness indicates that a drag reduction occurred. In addition, a 16% reduction in wall shear was evident for the mylar/compressor foam compliant surface.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; July 197
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  • 74
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    Stability characteristics of a single-phase free convection loop (1975)
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    Publication Date: 2011-08-16
    Description: Experiments investigating the stability characteristics of a single-phase free convection loop are reported. Results of the study confirm the contention made by previous workers that instabilities near the thermodynamic critical point can occur for ordinary fluids as well as those with unusual behavior in the near-critical region. Such a claim runs counter to traditional beliefs, but it is supported by the observation of such instabilities for water at atmospheric pressure and moderate temperatures in the present work.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 67; Jan. 14
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  • 75
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    Computation of turbulent flows (1976)
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    Publication Date: 2011-08-16
    Description: The essential ingredients and the effectiveness of several levels of turbulent-flow partial differential equation models are considered. Zero-equation models use only the partial differential equation (pde) for the mean velocity field and do not employ turbulence pde's. One-equation models make use of an additional pde relating to the turbulence velocity scale. Attention is also given to two-equation models, stress-equation models, and large eddy simulations. Large-eddy simulations are concerned with a three-dimensional time-dependent numerical computation of the large-scale turbulence.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 76
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    Drag coefficient equations for small particles in high speed flows (1975)
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    Publication Date: 2011-08-16
    Description: The paper determines the effect of various available drag coefficient equations on particle velocity calculations for typical two phase flows encountered in supersonic and turbulent laser velocimeter applications. The predictions of the particle drag coefficient equations are compared with experimental sphere drag data. For the laser velocimeter applications, the relative Mach number less than 2 and the relative Reynolds number less than 200 are of particular importance.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; Nov. 197
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  • 77
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    Mixing length in low Reynolds number compressible turbulent boundary layers (1975)
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    Publication Date: 2011-08-16
    Description: The paper studies the effect of low Reynolds number in high-speed turbulent boundary layers on variations of mixing length. Boundary layers downstream of natural transition on plates, cones and cylinders, and boundary layers on nozzle walls without laminarization-retransition are considered. The problem of whether low Reynolds number amplification of shear stress is a result of transitional flow structure is considered. It is concluded that a knowledge of low Reynolds number boundary layer transition may be relevant to the design of high-speed vehicles.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 13; Aug. 197
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  • 78
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    The low frequency sound from multipole sources in axisymmetric shear flows. II (1976)
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    Publication Date: 2011-08-16
    Description: A previous analysis of the acoustic radiation from multipole sources is extended to include additional components of the dipole and quadrupole sources. It is found that, unlike the components of the sources considered in the previous paper, the exponent of the Doppler factor now depends on the location of the sources within the jet.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 75; May 13
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  • 79
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    Re-examination of compliant wall experiments in air with water substrates (1976)
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    Publication Date: 2011-08-16
    Description: A possible alternative explanation is proposed for compliant wall drag reductions measured in previous investigations. Standing waves were observed to form on the surfaces of compliant wall models in air with water substrates as the freestream velocity was increased from 15 to 30 m/s. These waves resembled sine waves with half of the wave protruding over the upstream portion of the model and the other half being recessed over the downstream end of the model. These data coupled with results of recent drag reduction experiments suggest that standing waves could have caused a shift in the model center of gravity creating a bending moment that was interpreted as a reduction in the skin friction drag.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Spacecraft and Rockets; 13; Aug. 197
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  • 80
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    Laminar free convection over two-dimensional bodies with uniform surface heat flux (1976)
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    Publication Date: 2011-08-16
    Description: A general analysis is presented of the steady nondissipative constant-property laminar boundary layer flow over a two-dimensional body of uniform surface heat flux situated in an infinite ambient fluid of undisturbed temperature. The analysis is then applied to a long horizontal circular cylinder. Numerical solutions to the universal functions associated with the first two terms in the derived series are given for Prandtl numbers 0.7, 1, 3, 5, 7, and 10. The results are compared with those obtained by Koh (1964) whose method is patterned after the Blasius-Frossling procedure for forced convection flow. The study reveals that Wilks' (1972) analysis concerning the external natural convection about two-dimensional bodies with constant heat flux is in error.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Letters in Heat and Mass Transfer; 3; Jan
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  • 81
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    Fluid dynamic research at NASA-Ames Research Center related to transonic wind tunnel design and testing techniques (1976)
    In:  CASI
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    Publication Date: 2012-05-19
    Description: Fluid dynamic research with the objective of developing new and improved technology in both test facility concepts and test techniques is being reported. A summary of efforts and results thus far obtained in four areas is presented. The four area are: (1) the use of heavy gases to obtain high Reynolds numbers at transonic speeds: (2) high Reynolds number tests of the C-141A wing configuration; (3) performance and flow quality of the pilot injector driven wind tunnel; and (4) integration time required to extract accurate static and dynamic data from tests in transonic wind tunnels. Some of the principal conclusions relative to each of the four areas are: (1) Initial attempts to apply analytical corrections to test results using gases with gamma other than 1.4 to simulate conditions in air show promise but need significant improvement; (2) for the C-141A configuration, no Reynolds number less than the full scale flight value provides an accurate simulation of the full scale flow; (3) high ratios of tunnel mass flow rate to injection mass flow rate and high flow quality can be obtained in an injector driven transonic wind tunnel; and (4) integration times of 0.5 to 1.0 sec may be required for static force and pressure tests, respectively, at some transonic test conditions in order to obtain the required data accuracy.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Wind Tunnel Design and Testing Tech.; 8 p
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  • 82
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    Contribution of the National Aeronautics and Space Administration Langley Research Center (1975)
    In:  CASI
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    Publication Date: 2012-05-19
    Description: As part of a special international effort, three nozzles were designed and tested on single nacelle models in wind tunnels of several nations belonging to the North Atlantic Treaty Organization. All three of these nozzles were investigated in the Langley 16-foot transonic wind tunnel at the National Aeronautics and Space Administration's Langley Research Center. Langley Research Center also contributed theoretical calculations of the jet plume boundary and afterbody pressures. The calculations were obtained using an iterative solution which combined the inviscid Douglas Neumann method for the external flow with the method of characteristics for the flow in the jet plume. For the investigation, the nozzles were mounted on a single nacelle model 15.24 centimeters in diameter and 162.56 centimeters long. Tests were made at free stream Mach number from 0.4 to 1.2, and at Reynolds numbers per meter from 7.38 million to 13.78 million depending on the Mach number. Four types of data were recorded: afterbody pressure data, afterbody force data, model boundary layer data, and tunnel wall pressure data. The ratio of jet total pressure to free stream static pressure ranged up to 8.5. A description of the wind tunnel, model, and test procedure is included.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Improved Nozzle Testing Tech. in Transonic Flow; 9 p
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  • 83
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    Numerical techniques for the solution of the compressible Navier-Stokes equations and implementation of turbulence models (1975)
    In:  CASI
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    Publication Date: 2012-05-19
    Description: The time-splitting explicit numerical method of MacCormack is applied to separated turbulent boundary layer flow problems. Modifications of this basic method are developed to counter difficulties associated with complicated geometry and severe numerical resolution requirements of turbulence model equations. The accuracy of solutions is investigated by comparison with exact solutions for several simple cases. Procedures are developed for modifying the basic method to improve the accuracy. Numerical solutions of high-Reynolds-number separated flows over an airfoil and shock-separated flows over a flat plate are obtained. A simple mixing length model of turbulence is used for the transonic flow past an airfoil. A nonorthogonal mesh of arbitrary configuration facilitates the description of the flow field. For the simpler geometry associated with the flat plate, a rectangular mesh is used, and solutions are obtained based on a two-equation differential model of turbulence.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Computational Methods for Inviscid and Viscous Two-and-Three-Dimensional Flow Fields; 24 p
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  • 84
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    Predictive capabilities of series solutions for laminar free convection boundary layer heat transfer (1978)
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    Publication Date: 2011-08-17
    Description: Various types of series solutions for predicting laminar, free-convection boundary-layer heat transfer over both isothermal and nonisothermal boundaries are reviewed. The methods include finite difference, Merk series, Blasius series, and Goertler series. Comparative results are presented for heat transfer over an isothermal, horizontal, elliptical cylinder in both slender and blunt configurations.
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  • 85
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    Coefficient matrices for implicit finite difference solution of the inviscid fluid conservation law equations (1978)
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    Publication Date: 2011-08-17
    Description: Although the Navier-Stokes equations describe most flows of interest in aerodynamics, the inviscid conservation law equations may be used for small regions with viscous forces. Thus, Euler equations and several time-accurate finite difference procedures, explicit and implicit, are discussed. Although implicit techniques require more computational work, they permit larger time steps to be taken without instability. It is noted that the Jacobian matrices for Euler equations in conservation-law form have certain eigenvalue-eigenvector properties which may be used to construct conservative-form coefficient matrices. This reduces the computation time of several implicit and semiimplicit schemes. Extensions of the basic approach to other areas are suggested.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computer Methods in Applied Mechanics and Engineering; 13; Feb. 197
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  • 86
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    The Wiener-Hermite expansion applied to decaying isotropic turbulence using a renormalized time-dependent base (1978)
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    Publication Date: 2011-08-17
    Description: The problem of decaying isotropic turbulence has been studied using a Wiener-Hermite expansion with a renormalized time-dependent base. The theory is largely deductive and uses no modeling approximations. It has been found that many properties of large-Reynolds-number turbulence can be calculated (at least for moderate time) using the moving-base expansion alone. Such properties found are the spectrum shape in the dissipation range, the Kolmogorov constant, and the energy cascade in the inertial subrange. Furthermore, by using a renormalization scheme, it is possible to extend the calculation to larger times and to initial conditions significantly different from the equilibrium form. If the initial spectrum is the Kolmogorov spectrum perturbed with a spike or dip in the inertial subrange, the process proceeds to eliminate the perturbation and relax to the preferred spectrum shape. The turbulence decays with the proper dissipation rate, and several other properties are found to agree with measured data. The theory is also used to calculate the energy transfer and the flatness factor of turbulence.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 85; Mar. 21
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  • 87
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    Steady flow of a non-Newtonian fluid through a contraction (1978)
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    Publication Date: 2011-08-17
    Description: A steady-state analysis is conducted to examine the basic flow structure of a non-Newtonian fluid in a domain including an inflow region, a contraction region, and an outflow region. A Cartesian grid system is used throughout the entire flow domain, including the contraction region, thus creating an irregular grid cell structure adjacent to the curved boundary. At node points adjacent to the curved boundary symmetry conditions are derived for the different flow variables in order to solve the governing difference equations. Attention is given to the motion and non-Newtonian constitutive equations, the boundary conditions, the numerical modeling of the non-Newtonian equations, the stream function contour lines for the non-Newtonian fluid, the vorticity contour lines for the non-Newtonian fluid, the velocity profile across the contraction, and the shear stress contour lines for the non-Newtonian fluid.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics; 27; Apr. 197
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  • 88
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    Wall region of a relaxing three-dimensional incompressible turbulent boundary layer (1978)
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    Publication Date: 2011-08-17
    Description: A three-dimensional turbulent boundary layer relaxing behind a transverse hump (shaped as a 30-deg swept 5-ft chord wing-type model) was studied in a low-speed wind tunnel. Data obtained with hot-wire probes showed that the apparent dimensionless velocity profiles in the viscous sublayer prevail universally; evidence for wall similarity in the relaxing flow field was confirmed in the form of a log law. An unusual region of slightly decreasing cross-flow angle was found in collateral regions, and a near-wall noncollateral flow was posited. Streamwise relaxation of the mean flow field was also investigated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 85; Mar. 7
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  • 89
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    Monte Carlo turbulence simulation (1977)
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    Publication Date: 2011-08-17
    Description: The paper describes turbulence simulation experiments based on the principles of control system theory, that is, the construction of a system characterized by a system function such that upon exciting the system with prescribed noise processes the output of the system is a realization of a random processing the desired statistical attributes of turbulence. An experimental autocorrelation of Jimsphere measurements of wind velocity was approximated to simulate turbulent wind. From the approximate autocorrelation function, the required system function is obtained, and a discrete time system is designed. Another method of simulation is to solve the convolution integral by filter techniques. Other methods include discrete Fourier simulation and self-similar simulation.
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  • 90
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    Turbulence processes and simple closure schemes (1977)
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    Publication Date: 2011-08-17
    Description: The problem of closure in turbulence in the case of two-point correlations resides in the existence of two unknowns E and W, the energy spectrum function and the transfer function, respectively, in the spectrum equation. In the case of weak turbulence, W is negligible. In case of higher correlations, closure can be effective by neglecting the inertia term in the highest order term used. Specifying a certain number of spectra at an initial time is also a way of getting around the closure problem. A simple case of turbulent shear flow is then considered, where two-point correlation equations are used and the velocity is broken into mean and fluctuating components. This yields a differential equation for the energy spectrum, the three terms of which are the energy spectrum, production term and dissipation term. They are plotted for a particular time. Similar analyses and comparisons with experiment are made for pipe and boundary layer flows.
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  • 91
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    Laminar boundary-layer flow of non-Newtonian fluid (1979)
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    Publication Date: 2011-08-17
    Description: A solution for the two-dimensional and axisymmetric laminar boundary-layer momentum equation of power-law non-Newtonian fluid is presented. The analysis makes use of the Merk-Chao series solution method originally devised for the flow of Newtonian fluid. The universal functions for the leading term in the series are tabulated for n from 0.2 to 2. Equations governing the universal functions associated with the second and the third terms are provided. The solution together with either Lighthill's formula or Chao's formula constitutes a simple yet general procedure for the calculation of wall shear and surface heat transfer rate. The theory was applied to flows over a circular cylinder and a sphere and the results compared with published data.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer; 22; Oct. 197
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  • 92
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    Evolution of a rotating flow in the vicinity of a surface (1979)
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    Publication Date: 2011-08-17
    Description: Evolution of a rotating flow in a body of fluid bounded by a stationary flat surface is discussed. The calculated results show that the radial pressure gradient is substantially reduced in the region close to the surface, so that letting that gradient be independent of distance from the surface would be expected to give only rough or qualitative estimates. However, the reduced rotation near the stationary surface is still large enough to cause an inflow near the surface and to set up a recirculation pattern. The concentration of vorticity by the radial inflow is not great enough to increase the tangential velocities near the center of rotation.
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  • 93
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    Solitary waves in stratified shear flows (1979)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analysis is described of long, finite-amplitude internal waves in a stratified shear flow. Both regular and singular modes are considered with a nonlinear critical layer employed in the latter case. A three-layer model is used to develop the theory and closed-form expressions are obtained relating the phase speed to the Richardson number, the latter quantity being taken as O(1). The amplitude evolution equation is found to be either the Korteweg-de Vries equation or the Benjamin-Davis-Ono equation depending upon the distance of the more remote boundary from the edge of the shear layer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Geophysical and Astrophysical Fluid Dynamics; 13; 1-3,; 1979
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  • 94
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    An efficient explicit-implicit-characteristic method for solving the compressible Navier-Stokes equations (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Explicit, implicit, and characteristic finite-difference methods are applied to solve model equations representative of the compressible Navier-Stokes equations. An approach is then formulated for solving the Navier-Stokes equation at high Reynolds numbers. The approach has drastically reduced the computation time required to obtain viscous flow solutions. Computational results for shock wave separated flows are presented.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 95
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    The shape of a pendent liquid drop (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Formal solutions of the static equilibrium equations for the form of the outer surface of a pendent liquid drop are studied. An approach is adopted in which only the one-parameter family determined by vertex height (u sub 0) need be described. Attention is restricted to rotationally symmetric configurations, and all symmetric solutions are characterized for the case where the Lagrange parameter lambda is equal to zero. It is shown that for any u sub 0 the function u(r; u sub 0) can be extended as a parametric solution of a system of equations for all arc lengths, yielding a curve without limit sets or double points, and that the resulting capillary rotation surface spreads out indefinitely away from the axis r = 0. The asymptotic form of the surface in the case of large absolute values of u sub 0 is characterized quantitatively, along with the global structure of all such surfaces.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 96
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    Transient thermal response of ablating bodies (1979)
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    Publication Date: 2011-08-17
    Description: A numerical study of transient thermal response of a blunt-nosed axisymmetric body made of Teflon is presented using a two-layer thermal model. It is shown that phase change and transverse heat conduction have a considerable effect on the internal temperature field. Comparison of the numerical results with experimental data shows that the single-layer thermal model does not predict the real feature of the thermal field, whereas the results of the two-layer thermal model agree reasonably well with the experiment.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 17; Feb. 197
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  • 97
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    Comparison of a correlation term-discard closure for decaying homogeneous turbulence with experiment (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Turbulence decay is calculated by using experimental initial conditions and discarding quadruple-correlation terms in the correlation equations. Agreement with experiment is good only for moderately small times, but there are no perceptible negative spectral energies even at large times.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 22; Jan. 197
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  • 98
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    The computation of incompressible, three-dimensional flows in containers with extensible walls (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The theoretical study of flow in biological vascular systems is made very difficult in connection with local and temporal changes of the cross section. Experimental investigations with the aid of model tests are, however, not enough for a solution of the problems, and numerical solutions are more and more employed for a description of such flows. A description is presented of a difference procedure for the solution of the complete Navier-Stokes equations with curvilinear coordinates for three-dimensional flows in containers. The integration of the Navier-Stokes equations for flows in containers with rigid and moving walls is considered.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 99
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    Thermal response behavior of boundary-layer flows (1978)
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    Publication Date: 2011-08-17
    Description: This paper presents an approximate, but general, analysis for the thermal response behavior of incompressible, constant property, laminar boundary layer flow over a smooth object of arbitrary shape. It encompasses the classic time-dependent Leveque problem as its special case. Comparisons with available data show that, for fluids with Prandtl number of the order of unity or larger, this analytical solution is able to provide reasonably accurate results for most engineering applications. Under certain restrictive conditions, it can also be used to predict the thermal response of a compressible boundary layer flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer; 21; June 197
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  • 100
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    A finite element thermal analysis procedure for several temperature-dependent parameters (1978)
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    Publication Date: 2011-08-17
    Description: A finite-element thermal analysis procedure for elements with several temperature-dependent thermal parameters is presented. The procedure, based on an application of the Newton-Raphson iteration technique, is formulated by resolving element matrices into component matrices, one component for each thermal parameter. Component conductance matrices are evaluated by assuming constant thermal parameters within an element and are computed once per unit thermal parameter. Significant savings in computer time result from the unit thermal parameter concept. The solution procedure applied to a convectively cooled structure with significantly varying thermal parameters converged in four iterations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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