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  • Organic Chemistry  (693)
  • AERODYNAMICS  (460)
  • SOLAR PHYSICS  (258)
  • 1975-1979  (1,411)
  • 1976  (1,411)
Collection
Keywords
Publisher
Years
  • 1975-1979  (1,411)
Year
  • 1
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    Economy of flight at supersonic speeds (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: Prandtl's theory is used to determine the airflow over bodies and wings adapted to supersonic flight. By making use of these results, and by incorporating in them an allowance for the probable skin friction, some estimates of expected lift-drag ratios are made for various flight speeds with the best configuration. At each speed a slender body and wings having the best angle of sweepback are considered. For the range of supersonic speeds shown an airplane of normal density and loading would be required to operate at an altitude of the order of 60,000 feet. The limiting value of 1-1/2 times the speed of sound corresponds to a flight speed of 1000 miles per hour. At this speed about 1.5 miles per gallon of fuel are expected. It is interesting to note that this value corresponds to a value of more than 15 miles per gallon when the weight is reduced to correspond to that of an ordinary automobile.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 499-514
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  • 2
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    Aeroelastic characteristics of an oblique wing (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: In theory, the most efficient wing shape for transonic and low supersonic speeds is simply a long narrow straight subsonic wing turned at an oblique angle to the flight direction. This theory has been verified by tests at Mach numbers from .6 to 1.4 in supersonic wind tunnel and by comparative studies of transonic transport designs.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 867-883
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  • 3
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    Aerodynamic design for supersonic speeds (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: Recent theoretical and experimental work in supersonic aerodynamics is reviewed with its practical application in mind. Several arrangements of supporting surfaces and bodies are discussed and in some cases comparisons of theory and experiment are made. Finally, certain phenomena connected with lift and drag in a rarefied medium are considered briefly.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 625-644
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  • 4
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    Theoretical determination of the minimum drag of airfoils at supersonic speeds (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: A method is reported for determining mathematically the combined disturbance field, and in certain cases the minimum drag, of wings at supersonic speeds. The simplest analytic example is provided by the wing of elliptic planform, which achieves its minimum drag when the lift is distributed uniformly over the surface. With a symmetrical distribution of thickness, the requirement of minimum drag for a given total volume is found to lead to profiles of constant curvature.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 567-578
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  • 5
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    The minimum drag of thin wings in frictionless flow (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: The assumptions of the thin airfoil theory are found to provide certain necessary conditions for the minimum drag of airfoils having a given total lift, a given maximum thickness, or a given volume. The conditions are applicable to steady or unsteady motions and to subsonic or supersonic speeds without restriction on the planform. The computation of drag and the statement of the conditions for minimum drag depend on the consideration of a combined flow field, which is obtained by superimposing the disturbance velocities in forward and reversed motions. If the planform of the airfoil and its total lift are given, it is found that, for minimum drag, the lift must be distributed in such a way that the downwash in the combined field is constant over the entire planform. If the planform is given and the thickness of the airfoil is required to contain a specified volume, then the thickness must be distributed over the planform in such a way that the pressure gradient of the combined field in the direction of flight is constant at all points of the wing.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 557-565
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  • 6
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    Calculation of the motion of an airplane under the influence of irregular disturbances (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: The application of mathematical advances made in electricity and other branches to problems of airplane dynamics is demonstrated. The Heaviside-Bromwich methods of solution of linear differential equations are described and it is shown how these methods avoid the consideration of boundary conditions and of particular or complementary integrals. It is pointed out that if the solution of the differential equation is obtained for the case of a unit disturbance, the effect of varying disturbances may be found therefrom by Carson's theorem. A graphical solution of Carson's integral for irregular disturbances is given. The procedure of obtaining unit solutions of the equations is then taken up and the analogy between Heaviside's symbolic series solution and a physical procedure of approximation is shown. It is suggested that a fictitious impulsive disturbance be used in the treatment of initial motions.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 21-29
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  • 7
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    Three-dimensional wings of minimum pressure drag (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: In linearized flow theory, certain very interesting extremal properties of wings can be derived under rather broad conditions without the use of a complicated mathematical apparatus. The present chapter reviews certain results of this theory and indicates some rather obvious extensions to incorporate various auxiliary conditions. Several examples illustrating the relation between the geometrical features of the wing and the lift distribution for minimum drag are given.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Collected Works of Robert T. Jones; p 645-656
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  • 8
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    Some recent developments in the aerodynamics of wings for high speeds (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: The items discussed are: (1) a recently proposed correction formula for the effect of compressibility in two dimensional subsonic flow; (2) the equivalence rule and the area rule for transonic speeds; (3) reciprocal relations in linearized wing theory; and (4) some general results connected with the problem of minimum wave resistance. The paper concludes with an example showing indentation of the fuselage to obtain favorable interference with the wing at supersonic speeds.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 601-608
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  • 9
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    Theoretical correction for the lift of elliptic wings (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: In the wing section theory the magnitude of the circulation, and hence of the lift, is determined by the velocity that would be induced near the trailing edge of the section in a non-lifting potential flow. In three dimensional flow the problem is complicated by the presence of the wake and no simple basic solution has been found. Treatment of the problem of a wing of finite span is reported on the basis of the two dimensional theory, corrected for the effect of the wake.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 245-249
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  • 10
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    Reduction of wave drag by antisymmetric arrangement of wings and bodies (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: In theory, antisymmetric arrangements of wings and bodies can have smaller wave drag than corresponding mirror-symmetric arrangements. Thus, a long narrow oblique wing which presents the same aspect for two opposite directions of flight is potentially more efficient than corresponding (i.e., structurally equivalent) swept wing. The single continuous wing panel also adapts itself more readily to varying angles of obliquity, and hence, to varying flight speeds. Previous work on the aerodynamics and flight stability of oblique wing combinations is reviewed and a possible mode of application to transport aircraft operating at moderate supersonic speeds is suggested.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 657-664
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  • 11
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    The compressibility rule for drag of airfoil noses (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: It is shown that the drag of any semi-infinite airfoil section in purely subsonic inviscid flow follows precisely the Prandtl-Glauert compressibility rule. The result for the parabola has application to leading edge corrections in thin airfoil theory.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 619-623
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  • 12
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    Possibilities of efficient high-speed transport airplanes (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: Comparisons of wing-body combinations may not disclose the full effect of a loss in aerodynamic efficiency. If the thrust needs to be increased at a given altitude then more or larger engines will have to be used and the possibility of concealing them becomes less. In this process the lift drag ratio of the complete airplane may become still more unfavorable than indicated by the comparison. Primarily aerodynamic and structural considerations point toward the development of turbojet engines specifically adapted to operation in an atmosphere of one tenth normal density. In addition to the numerous other technological problems associated with operation at these high altitudes, the problems of safe descent and effective limitation to low speeds at low altitudes seem important.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 579-592
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  • 13
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    Leading-edge singularities in thin-airfoil theory (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: If the thin airfoil theory is applied to an airfoil having a rounded leading edge, a certain error will arise in the determination of the pressure distribution around the nose. It is shown that the evaluation of the drag of such a blunt nosed airfoil by the thin airfoil theory requires the addition of a leading edge force, analogous to the leading edge thrust of the lifting airfoil. The method of calculation is illustrated by application to: (1) The Joukowski airfoil in subsonic flow; and (2) the thin elliptic cone in supersonic flow. A general formula for the edge force is provided which is applicable to a variety of wing forms.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 533-538
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  • 14
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    The use of conical and cylindrical fields in supersonic wing theory (1976)
    In:  CASI
    Details
    Publication Date: 2010-11-08
    Description: Some of the recent advances in the theory of thin airfoils are presented with particular reference to extensions of the theory to three dimensional flows and to supersonic speeds. The problem discussed herein is the calculation of the small disturbance velocities u, v, and w in the external field produced by the flight velocity V of the airfoil.
    Keywords: AERODYNAMICS
    Type: Collected Works of Robert T. Jones; p 483-497
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  • 15
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    Some basic considerations of measurements involving collimated direct sunlight (1976)
    In:  CASI
    Details
    Publication Date: 2006-08-09
    Description: For abstract, see N77-26622.
    Keywords: SOLAR PHYSICS
    Type: Terrest. Photovoltaic Meas., 2; p 233-246
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  • 16
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    The solar spectrum at typical clear weather days (1976)
    In:  CASI
    Details
    Publication Date: 2006-08-09
    Description: The solar spectrum in the range of 300 is less than lambda is less than 1500nm is given for five typical clear weather days. These days are selected to represent typical seasonal conditions in respect to airmass water vapor, ozone, and turbidity. Present data are reviewed, and specific conditions are selected. The spectral distribution of the irradiance is given for the direct component, the scattered skylight, the total flux on a horizontal surface, and the flux on an inclined surface normal to the direct beam.
    Keywords: SOLAR PHYSICS
    Type: NASA. Lewis Res. Center Terrest. Photovoltaic Meas., 2; p 17-58
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  • 17
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    Monitoring solar radiation: The ERDA program (1976)
    In:  CASI
    Details
    Publication Date: 2006-08-09
    Description: An overview of the Energy Research and Development Administration planned insolation data network is described. The design of the network is predicated on an analysis and definition of user requirements. Research and analysis projects covering data collection, forecasting and extrapolation are presented.
    Keywords: SOLAR PHYSICS
    Type: NASA. Lewis Res. Center Terrest. Photovoltaic Meas., 2; p 1-17
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  • 18
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    Artificial solar eclipse experiment MA-148 (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: On July 19, 1975, the Apollo spacecraft successfully occulted the solar disk from the field of view of a camera mounted in the Soyuz spacecraft while performing a spacecraft separation maneuver to permit the outer solar corona to be viewable by the Soyuz camera. The camera operated automatically, and 55 frames were developed for scientific analysis.
    Keywords: SOLAR PHYSICS
    Type: Apollo-Soyuz Test Project; 5 p
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  • 19
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    Stratospheric aerosol measurement experiment MA-007 (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The Apollo Soyuz Test Project Stratospheric Aerosol Measurement Experiment was flown to demonstrate that direct solar occultation measurements by photometers and photographs can be used for defining stratospheric aerosol concentrations. Supporting ground truth data were provided by laser radar and balloon borne dustsonde. Initial results show a significant difference in aerosol concentrations between the Northern and Southern Hemispheres.
    Keywords: SOLAR PHYSICS
    Type: Apollo-Soyuz Test Project; 8 p
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  • 20
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    The lateral flying qualities of the Bell XP-77 airplane as estimated from full-scale tunnel tests, 16 June 1944 (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Results are presented for tests made of the full scale model of the airplane in the NACA full scale tunnel. These tests were planned so as to cover as completely as possible the lateral flying quality requirements for pursuit-type airplanes contracted for by the United States Army Air Forces.
    Keywords: AERODYNAMICS
    Type: Collected Works of Charles J. Donlan; 23 p
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  • 21
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    Three dimensional boundary layer separation in supersonic flow (1976)
    In:  CASI
    Details
    Publication Date: 2011-10-14
    Description: An account is given of a detailed experimental investigation of three dimensional boundary layer separation in supersonic flow. In investigating three dimensional effects on supersonic separation, models were chosen which exhibited departures from two dimensional flow in the simplest way. The plane compression corner was replaced by a plate attached to a swept back wedge formed by two obliquely intersecting planes. Maintaining a constant tunnel Mach number of 2.5, surface pressure measurements were made on these models at static orifices spaced along the centerline and along three parallel lines. The flow parameters in the boundary layer and separated regions adjacent to the model surface were measured by traversing hot wire and pitot probes. The traverses were taken across the boundary layer and reversed flow regions in a direction normal to the body surface; they were made in several vertical planes, including the plane of symmetry.
    Keywords: AERODYNAMICS
    Type: AGARD Flow Separation; 13 p
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  • 22
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    DSS 14 operating noise temperature during Helios 1 near-sun tracking (1976)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: When spacecraft are tracked near the line-of-sight of the sun, the ground antenna sidelobes see the solar noise. The solar noise increases the ground system operating noise temperature and degrades the downlink RF reception performance. At specific antenna azimuthal angles relative to the sun, noise peaks and nulls occur periodically throughout a day's tracking pass due to the quadripod support leg-generated sidelobes. This article documents this effect while tracking Helios 1, illustrates the time of the peaks, and compares the predicted time of the noise temperature peaks with the measured data.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 68-76
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  • 23
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    The solar wind and its influence on the atmospheres of moon, Mercury and Venus (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The solar wind is expected to have an important influence on the atmospheres of the moon, Mercury and Venus and therefore a brief outline of solar wind theory is presented along with the predicted properties of the wind at the orbits of these planets. Since the atmospheres of the moon and possibly Mercury are formed primarily by solar wind accretion, we present the latest accretion models for these bodies. The expected role the solar wind plays on both the ionization and termination of the ionosphere of Venus is discussed.
    Keywords: SOLAR PHYSICS
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  • 24
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    Numerical solution of the steady-state Navier-Stokes equations for hypersonic flow about blunt axisymmetric bodies (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The steady-state Navier-Stokes equations are solved for hypersonic flow about blunt axisymmetric bodies. The equations of motion are solved by successive approximations using an implicit finite-difference scheme. The results are compared with viscous shock-layer theory, experimental data, and time-dependent solutions of the Navier-Stokes equations. It is demonstrated that viscous shock-layer theory is sufficiently accurate for the range of flight conditions normally encountered by entry vehicles.
    Keywords: AERODYNAMICS
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  • 25
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    The solar brightness temperature at millimeter wavelengths (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Measurements of the brightness temperature of the sun near 36 GHz and 93 GHz were made using the new moon as a calibration source. Provided the brightness temperature of the moon is known and all measurements are reduced to the same zenith angle, a simple expression can be used for the sun-to-new moon ratio which is independent of antenna gain, atmospheric absorption and reemission, and radiometer calibration constants. This ratio was measured near 36 GHz and at two frequencies near 93 GHz with a Dicke switched superheterodyne radiometer system and a 2.4 m Cassegrain antenna. The slopes of the solar brightness temperature spectrum based on these ratios were measured. The absolute solar brightness spectrum derived from all current available measurements supplemented by the present ones is also plotted and discussed.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 48; May 1976
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  • 26
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    Aerodynamic heat transfer to a hypersonic research aircraft model /X-24C/ at Mach 6 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper reports on results of heat-transfer tests conducted on a 1/29-scale model of the X-24C-12I hypersonic research aircraft configuration in a Mach 6 tunnel at a Reynolds number of thirteen million using the phase-change heat transfer technique. Sequences of phase-change heat transfer pattern photographs are presented showing windward side and leeward side heating processes. Theoretical predictions of dimensionless heat transfer coefficients along a data line on lower fuselage and on fuselage side bracket the experimental values. A turbulent heating theory gives good agreement with data when shifted to a new virtual origin.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 13; Dec. 197
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  • 27
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    Skin friction on a flat perforated acoustic liner (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The report concerns the measurement of friction coefficients of a typical perforated acoustic liner installed in the side of a wind tunnel. The results are compared with measured friction coefficients of a smooth hard wall for the same mean flow velocities in a wind tunnel. At a velocity of 61 m/sec, an increase in the local skin coefficient of only a few percent was observed, but at the highest velocity of 213 m/sec an increase of about 20% was obtained. This velocity is a realistic velocity for turbo-machinery components utilizing such liners, so a loss in performance is to be expected. Some tests were also performed to see if changes in the mean boundary layer induced by imposed noise would result in friction increase, but only at low velocity levels was such an increase in friction noted.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 14; Nov. 197
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  • 28
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    Steady supersonic flowfields with embedded subsonic regions (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Supersonic flow past a blunt body is considered, where the flow contains an embedded subsonic region which lies between the shock wave and the body surface and is bounded by sonic lines from the body to the shock. A numerical approach is taken, which uses a basic finite difference scheme that solves the unsteady fluid dynamic equations in integral form. The unsteady equations are everywhere hyperbolic in time so no distinction need be made between subsonic and supersonic regions. Solutions to the mixed elliptic and hyperbolic steady flow equations are approached asymptotically in time. The method is illustrated for two-dimensional flows.
    Keywords: AERODYNAMICS
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  • 29
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    Evidence for the regulation of solar wind heat flux at 1 AU (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observational evidence favoring the local regulation of solar-wind heat flux at 1 AU is reviewed, and four months of IMP 6 plasma and magnetic-field data are merged and analyzed in order to investigate what might be regulating the heat flux. A statistical analysis of the data shows that the solar-wind Alfven speed is probably regulating the heat flux locally at 1 AU and that the Alfven speed, the velocity difference between the peak of low-energy electrons and the bulk plasma velocity, and the solar-wind velocity component projected along the local spiral angle are statistically well correlated for Alfven speeds not exceeding about 70 km/s. A time-series analysis of the data indicates that only the Alfven speed and the velocity difference between the peak of low-energy electrons and the bulk plasma velocity are well correlated both qualitatively and quantitatively on a microscopic time scale. It is strongly suggested that, at times, the solar-wind heat flux is locally regulated by the magnitude of the Alfven speed at 1 AU. Uncertainties in the results are discussed.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Oct. 1
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  • 30
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    High-speed solar wind flow parameters at 1 AU (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Nineteen high-speed solar-wind streams observed at 1 AU between March 1971 and July 1974 are studied to develop a more realistic set of constraints for theories on such streams. The streams were chosen because their speeds exceeded 650 km/s for at least several consecutive three-hour periods and because their properties met certain other criteria. A comparison of average stream parameters with predictions of existing steady-state models shows that no single model is adequate to explain the observations. In particular, it is found that no existing model consistent with reasonable coronal conditions predicts the particle fluxes, the convected proton bulk-flow-energy fluxes, and the convected proton enthalpy fluxes observed at 1 AU when the flow speed exceeds 650 km/s.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Oct. 1
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  • 31
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    Forbidden transition probabilities for ground terms of ions with p or p5 configurations (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Forbidden transition probabilities are given for ground term transitions of ions in the isoelectronic sequences with outer configurations 2s2 2p (B I), 2p5 (F I), 3s2 3p (Al I), and 3p5 (Cl I). Tables give, for each ion, the ground term interval, the associated wavelength, the quadrupole radial integral, the electric quadrupole transition probability, and the magnetic dipole transition probability. Coronal lines due to some of these ions have been observed, while others are yet to be observed. The tales for the Al I and Cl I sequences include elements up to germanium.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 46; Jan. 197
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  • 32
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    Hectometric and kilometric solar radio emission observed from satellites in August 1972 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Type II, type III, and continuum solar radio events, as well as intense terrestrial magnetospheric radio emissions, were observed at low frequencies (10 MHz to 30 kHz) by the IMP-6 satellite during the period of high solar activity in August 1972. This review covers briefly the unique direction-finding capability of the experiment, a detailed chronology of the low-frequency radio events, and, where possible, their association with both ground-based radio observations and solar flares. The attempted observation of solar bursts in the presence of intense magnetospheric noise may, as illustrated, lead to erroneous results in the absence of directional information. The problem of assigning an electron-density scale and its influence on determining burst trajectories is reviewed. However, for the disturbed conditions existing during the period in question, it is felt that such trajectories cannot be determined accurately by this method. The capabilities, limitations, and observing programs of present and future satellite experiments are briefly discussed.
    Keywords: SOLAR PHYSICS
    Type: Space Science Reviews; 19; Oct
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  • 33
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    Diamagnetic boundary layers - A kinetic theory (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A kinetic theory is presented for boundary layers associated with MHD tangential 'discontinuities' in a collisionless magnetized plasma, such as those observed in the solar wind. The theory consists of finding self-consistent solutions of Vlasov's equation and Maxwell's equation for stationary one-dimensional boundary layers separating two Maxwellian plasma states. Layers in which the current is carried by electrons are found to have a thickness of the order of a few electron gyroradii, but the drift speed of the current-carrying electrons is found to exceed the Alfven speed, and accordingly such layers are not stable. Several types of layers in which the current is carried by protons are discussed; in particular, cases are considered in which the magnetic-field intensity, direction, or both, changed across the layer. In every case, the thickness was of the order of a few proton gyroradii, and the field changed smoothly, although the characteristics depended somewhat on the boundary conditions. The drift speed was always less than the Alfven speed, consistent with stability of such structures. These results are consistent with observations of boundary layers in the solar wind near 1 AU.
    Keywords: SOLAR PHYSICS
    Type: Astrophysics and Space Science; 45; Dec. 197
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    The solar physics Shuttle/Spacelab program and its relationship to studies of the flare build-up (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The main phase of solar physics (including flare-buildup) research on Shuttle/Spacelab during the 1980s centers around the use of facility instruments for multiple-user, multiple flight operations. Three main facilities are being considered: a meter-class optical telescope for visible and near-UV wavelengths, an EUV/XUV/soft X-ray facility, and a hard X-ray imaging facility (including a full-sun 5-600 keV spectrometer, a nuclear gamma ray spectrometer, and an X-ray polarimeter for the 5-100 keV range). Smaller instruments designed for specific observations and other classes of instruments such as solar monitors that are not on the facility level are also being considered.
    Keywords: SOLAR PHYSICS
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  • 35
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    Improved interactive calculation procedure for supersonic flows (1976)
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    Publication Date: 2011-08-17
    Description: An interactive numerical procedure has been developed for supersonic viscous flows (either two-dimensional or axisymmetric configurations). The flow field is divided into two regions: (1) an inner region which is highly viscous and mostly subsonic, and (2) an outer region where the flow is supersonic and in which viscous effects are small, but not negligible. This paper presents a detailed description of: I. Outer Region - numerical solution obtained by applying the method of characteristics to a system of equations which includes viscous and conduction transport terms only normal to the streamlines; II. Inner Region - treated by a system of equations of the boundary-layer type that includes higher order effects, such as longitudinal and transverse curvature and normal pressure gradients (equations are coupled and solved simultaneously in physical coordinates, using an implicit finite-difference scheme); III. Interactive Procedure - in the interaction mode, the two regions are coupled iteratively along a matching line, where the Mach number is of the order of 1.2.
    Keywords: AERODYNAMICS
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  • 36
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    The 1976 Helios and Pioneer solar conjunctions-continuing corroboration of the link between Doppler noise and integrated signal path electron density (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observed Doppler noise (rms phase jitter) from the 1976 solar conjunctions of the Helios 1 and 2 and the Pioneer 10 and 11 spacecraft was processed with a recently developed Doppler noise model ISEDB. Good agreement is obtained between the observed data and the model. Correlation is shown between deviations from the ISEDB model and sunspot activity, but it is insufficient to be modeled. Correlation is also shown between ISEDB model deviations for (spacecraft) signal paths on the same side of the sun.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 121-137
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  • 37
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    Interplanetary disturbances caused by the August 1972 solar flares as observed by Pioneer 9 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Pioneer 9 plasma and field observations at 0.78 AU were used as the basis of the analysis of the dynamic behavior of the interplanetary medium during early August, 1972. The following investigations were carried out: (1) energy and mass estimates for the solar flares of Aug. 2, 4, and 7; (2) shock wave characteristics; and (3) a numerical simulation of the first two flare-generated disturbances on Aug. 2, 4, and 7.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Sept. 1
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  • 38
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    Structure of the extended solar magnetic field and the sunspot cycle variation in cosmic ray intensity (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: It is proposed that a relation exists between the extent of interplanetary-magnetic-field sectors and observed variations in cosmic-ray intensity at earth. Changes that take place in the sector magnetic fields and solar polar fields during a sunspot cycle are described. It is argued that a geometrical effect arising from changes in sector-field and polar-field extent during sunspot cycles may be the principal cause of the 11-yr modulation of cosmic-ray intensity observed at earth. The fraction of the heliosphere occupied by sector fields is estimated as a function of time through an average sunspot cycle, the solid angle of the heliosphere occupied by the extended solar polar fields is plotted through the same cycle, and monthly averages of observed absolute intensities of primary cosmic rays with a rigidity greater than 0.5 GV are compared with the plot of polar-field extent. It is found that the average sunspot-cycle variation of the solid angle of the extended polar fields is rather similar to the observed variation in the flux of the cosmic rays considered.
    Keywords: SOLAR PHYSICS
    Type: Nature; 262; Aug. 26
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  • 39
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    Influence of nonconservative differencing on transonic streamline shapes (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A computer program recently developed by South and Brandt (1976) which contained the Murman (1973) conservative finite-difference scheme is easily modified to use the Garabedian and Korn (1971) nonconservative finite difference scheme. This program solves the transonic small disturbance equation for only symmetric flow, but incorporates several iterative solution techniques. Results are presented for the case where the equally spaced computational grid extended to infinity in both the streamwise and normal directions. Streamline shapes are obtained along several grid lines by a streamwise integration of the normal component of the perturbation velocity. Comparison cases are run for a 10% thick parabolic arc airfoil at zero incidence for freestream Mach numbers of 0, 0.70, 0.84, and 0.95. It is shown that the use of a nonconservative finite-difference scheme in transonic flow calculations destroys the global mass balance when shocks are present. This lack of mass balance may prove to be more crucial in the case of an unconfined external flow.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 14; Aug. 197
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  • 40
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    Coronal temperatures and temperature gradients from OSO-7 spectroheliograms (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Temperatures and temperature gradients for the outer corona are obtained from brightness gradients of EUV lines that were measured with the spectroheliograph on OSO-7. Brightness gradients show considerable deviations from isothermal model calculations that include collisional excitation and photoexcitation. A negative temperature gradient that gives both positive and negative ion-abundance gradients appears to be able to account for the discrepancy. For the 284-A of Fe XV, perhaps the strongest line from the outer corona, measurements during 1972 appear to be consistent with a temperature near 2.3 million K near the equator at about 1.3 solar radii from the solar center and with temperature-gradient values near -0.7 that extend from as low as 1.2 to about 1.8 solar radii. Temperatures from strong lines of Fe XIV and Fe XVI indicate that variations of about 200,000 K exist along lines of sight where emission is appreciable. There appears to be some agreement between these results and temperature measurements from ion abundances in the solar wind and the Doppler width of the 5303-A line.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 47; Apr. 197
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  • 41
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    Limb-brightening observations from the OSO-7 satellite. II - Comparison of Abel-inverted intensities of Fe XIV and Fe XIII EUV emission lines with predictions (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Intensities of Fe XIV and Fe XIII EUV emission lines obtained at coronal locations beyond the limb by the Goddard spectroheliograph on the OSO 7 satellite have been corrected for the wavelength dependence of the instrument's sensitivity and have been Abel-inverted to provide a valid comparison with theoretical predictions for each ion. Details of the Abel-inversion procedure are given, including explicit formulas for application of Bracewell's (1956) method. The intensity ratios of pairs of lines originating from a common level are compared with expected theoretical transition probability ratios over a range of heliocentric distance; deviations in some cases yield information about adjacent unclassified lines. Comparison of the observations with predictions for Fe XIV and Fe XIII shows generally good agreement, with a few interesting discrepancies that may imply a corresponding need for more accurate collisional excitation cross sections. The same comparison yields the variation of electron density with heliocentric radius for each ion separately; the two density functions are found to agree within a factor of three.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 53; 2, De; Dec. 197
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  • 42
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    On the theory of the type III burst exciter (1976)
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    Publication Date: 2011-08-17
    Description: In situ satellite observations of type III burst exciters at 1 AU show that the beam does not evolve into a plateau in velocity space, contrary to the prediction of quasilinear theory. The observations can be explained by a theory that includes mode coupling effects due to excitation of the parametric oscillating two-stream instability and its saturation by anomalous resistivity. The time evolution of the beam velocity distribution is included in the analysis.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 46; Feb. 197
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  • 43
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    Directivity of low frequency solar type III radio bursts (1976)
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    Publication Date: 2011-08-17
    Description: The occurrence rate of type III solar bursts in the frequency range 4.9 MHz to 30 kHz is analyzed as a function of burst intensity and burst arrival direction. We find that (1) the occurrence rate of bursts varies inversely with the 1.5 power of the flux, and (2) the distribution of burst arrival directions at each frequency shows a significantly larger number of bursts observed west of the earth-sun line than east of it. This western excess in occurrence rate appears to be correlated with the direction of the average interplanetary magnetic field, and is interpreted as beaming of the observed burst radiation along the magnetic field direction.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 46; Feb. 197
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  • 44
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    The quiet sun chromospheric network observed from Skylab (1976)
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    Publication Date: 2011-08-16
    Description: The paper analyzes spectra of a supergranulation cell interior and cell boundary obtained near the solar center at wavelengths between 1200 and 1560 A with a normal-incidence spectrograph aboard Skylab. Absolute intensities, relative intensities, and profiles are given for selected optically thin and optically thick lines over the cell interior, the boundary, and intermediate positions; the results are compared with spectra obtained at the limb. Characteristic lengths along the line of sight are derived for the Si III emitting region, and these are compared with the predictions of Gabriel's (1975) model. It is concluded that the present data are representative of a fairly typical cell interior and boundary, that nonthermal motions are isotropic and the same for the interior and boundary, and that the electron-density ratio between the interior and the boundary is about a factor of two or less.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 209; Oct. 1
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  • 45
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    Vortex shedding from a blunt trailing edge with equal and unequal external mean velocities (1976)
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    Publication Date: 2011-08-16
    Description: A flow-visualization study has shown that strong Karman vortices develop behind the blunt trailing edge of a plate when the free-stream velocities over both surfaces are equal and that the vortices tend to disappear when the surface velocities are unequal. This observation provides an explanation for the occurence and disappearance of certain discrete tones often found to be present in the noise spectra of coaxial jets. Both the vortex formation and the tones occur at a Strouhal number based on the lip thickness and the average of the external steady-state velocities of about 0.2. Results from theoretical calculations of the vortex formation, based on an inviscid incompressible analysis of the motion of point vortices, were in good agreement with the experimental observations.
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 75; June 25
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  • 46
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    Doppler wavelength shifts of transition zone lines measured in Skylab solar spectra (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Wavelengths of lines of the transition-zone ions Si IV, C IV, O IV, N V, and O V are observed to be redshifted relative to the wavelengths of chromospheric lines in XUV spectra obtained from the normal-incidence spectrograph on Skylab. The spectra cover the wavelength range from 1200 to 1565 A and were obtained with the slit positioned over chromospheric network and cell regions, on coronal holes, and above the limb. The network-area and coronal-hole spectra were obtained near the disk center. Only some of the spectra show redshifted transition-zone lines. The observed shifts are between 0.03 and 0.08 A, implying velocities of 15 km/s or less. The amount of wavelength shift does not always appear to be the same for lines of different ions. The shifts imply that descending plasma in the solar atmosphere produces more emission than ascending plasma at temperatures between approximately 70,000 and 200,000 K.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 205; May 1
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  • 47
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    The emission-line spectrum above the limb of the quiet sun - 1175-1940 A (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Spectra of a quiet solar region obtained at positions within and above the solar white-light limb in the wavelength region from 1175 to 1940 A are discussed. The spectra were obtained by the slit spectrograph (SO82-B) on Skylab. The spectral resolution is 0.06 A, and the projected slit area on the sun was 2 x 60 arcsec (1450 x 43500 km). Relative line intensities are presented for lines formed in the temperature region of the solar atmosphere from about 8000 to 220,000 K. Representative line profiles of both optically thin and optically thick lines are shown as a function of height above the limb. Random mass-motion velocities are deduced from the optically thin lines, and the relative intensities and profiles of the lines are discussed in terms of current theoretical models. A wavelength list with identifications is given for the spectrum obtained at +4 arcsec above the white-light limb.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal Supplement Series; 31; July 197
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  • 48
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    Solar irradiance - Total and spectral and its possible variations (1976)
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    Publication Date: 2011-08-16
    Description: The present status of our knowledge of the total and spectral irradiance of the sun is briefly reviewed. The currently accepted NASA/ASTM standard values of the solar constant and the extraterrestrial solar spectral irradiance are presented. The uncertainties in these values are relatively high. Data on the variability of the solar constant are conflicting and inconclusive. The variability of solar spectral irradiance is almost totally unknown and unexplored. Some alleged sun-weather relationships are cited in support of the need to know more precisely the variations in total and spectral solar irradiance. An overview of the solar monitoring program of NASA is presented, with special emphasis on the Solar Energy Monitor in Space (SEMIS) experiment which has been proposed for several spacecraft missions. The monitor is a combination of a solar-constant detector and a prism monochromator.
    Keywords: SOLAR PHYSICS
    Type: Applied Optics; 15; Apr. 197
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  • 49
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    Solar gamma-ray lines as probes of accelerated particle directionalities in flares (1976)
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    Publication Date: 2011-08-16
    Description: Anisotropies of charged particles accelerated in solar flares can be studied by observing Doppler shifts of selected gamma-ray lines. The spectral shape of the 6.1-MeV line of O-16 is calculated. If the accelerated particles are isotropic, the line remains centered at an emitting-nucleus rest-frame energy of 6129.4 keV, and its width (FWHM) is about 100 keV. However, for particle anisotropies that may be produced in solar flares, the line is shifted to lower energies by about 30 to 40 keV.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 203; Feb. 1
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  • 50
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    Atmospheric entry into Jupiter's atmosphere in view of recent flyby results (1976)
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    Publication Date: 2011-08-16
    Description: The paper examines the heating levels experienced by a probe entering Kliore's (1974) model of Jupiter's atmosphere and compares the results with those of the Jupiter model atmospheres given elsewhere (NASA SP-8069, 1971), with the heating levels of Tauber (1969) and Tauber and Wakefield (1971). The computations are made using a point-mass atmospheric entry trajectory program, i.e., the Allen-Eggers (1958) analysis and simple correlations of heating. Results of heating calculations are compared and discussed. It is found that the warm temperature bulge exists at a level too low in the atmosphere to affect any heating and that the nominal atmosphere fits Kliore's model atmosphere best insofar as heating is concerned. Previous estimates of the heating levels to be expected for a probe entering Jupiter's atmosphere are therefore unaffected by Kliore's postulated atmospheres.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 13; Feb. 197
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  • 51
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    Roughness induced transition criteria for space shuttle-type vehicles (1976)
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    Publication Date: 2011-08-16
    Description: Tripping effectiveness of surface roughness on a delta wing shuttle orbiter model at 20 deg angle of attack is compared to that on plane and axisymmetrical bodies with and without longitudinal pressure gradients. The experimental data presented are compared on the basis of effective roughness Reynolds number since this parameter is not sensitive to flow conditions downstream of the roughness. The discussion covers the effective roughness Reynolds number as a function of roughness position Reynolds number, effective size ratio as a function of pressure gradient and distance from vehicle nose, and effect of spanwise roughness position on roughness effectiveness. It is shown that conventional criteria for sizing roughness elements which promote transition in two-dimensional zero-pressure gradient flows are insufficient for high-pressure gradient flows and three-dimensional flows. Roughness much smaller than that given by conventional criteria can cause transition and significantly increase the heating load.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 13; Feb. 197
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  • 52
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    A complete second-order theory for the unsteady flow about an airfoil due to a periodic gust (1976)
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    Publication Date: 2011-08-16
    Description: A uniformly valid second-order theory is developed for calculating the unsteady incompressible flow that occurs when an airfoil is subjected to a convected sinusoidal gust. Explicit formulas for the airfoil response functions (i.e., fluctuating lift) are given. The theory accounts for the effect of the distortion of the gust by the steady-state potential flow around the airfoil, and this effect is found to have an important influence on the response functions. A number of results relevant to the general theory of the scattering of vorticity waves by solid objects are also presented.
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 74; Apr. 22
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  • 53
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    The emission-line spectrum above the limb of a solar coronal hole - 1175-1940 A (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Emission-line spectra of a coronal hole that coincided with the north pole of the sun are discussed which were obtained with a slit spectrograph aboard Skylab at positions within and above the solar white-light limb in the wavelength range from 1175 to 1940 A. Relative line intensities, line profiles, and full widths at half-maximum are presented for selected chromospheric and transition-zone lines observed above the present polar coronal hole. Average mass motions in the transition zone are determined as a function of electron temperature from the widths of the optically thin lines by assuming ionization equilibrium. The line intensities and profiles are compared with corresponding results deduced from spectra obtained above a quiet solar region. The coronal-hole spectra are found to imply an angular dependence for the source function as well as a radial dependence such that the source function is the smallest at the south pole and increases with decreasing solar latitude.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal Supplement Series; 31; July 197
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  • 54
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    A technique for accelerating iterative convergence in numerical integration, with application in transonic aerodynamics (1976)
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    Publication Date: 2011-08-16
    Description: A technique is described for the efficient numerical solution of nonlinear partial differential equations by rapid iteration. In particular, a special approach is described for applying the Aitken acceleration formula (a simple Pade approximant) for accelerating the iterative convergence. The method finds the most appropriate successive approximations, which are in a most nearly geometric sequence, for use in the Aitken formula. Simple examples are given to illustrate the use of the method. The method is then applied to the mixed elliptic-hyperbolic problem of steady, inviscid, transonic flow over an airfoil in a subsonic free stream.
    Keywords: AERODYNAMICS
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  • 55
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    Inlets for high angles of attack (1976)
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    Publication Date: 2011-08-16
    Description: Different inlet designs for high angle of attack STOL and VTOL applications were tested in a subsonic wind tunnel. Three removable entry lips having contraction ratios of 1.30, 1.34 and 1.38 were tested with a single diffuser. The internal contour of each entry lip was an ellipse with a major to minor axis of 2.0. Each lip and diffuser assembly was tested to determine its tolerance to angle of attack, first with a conventional centerbody and then with an extended centerbody. Results indicate that a large improvement in separation angle (determined as a function of lip contraction ratio and inlet flow) was obtained for the extended centerbody for all contraction ratios. Improved inlet tolerance to angle of attack was obtained by reducing the adverse pressure gradient downstream of the throat.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 13; Apr. 197
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  • 56
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    Electron parameter correlations in high-speed streams and heat flux instabilities (1976)
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    Publication Date: 2011-08-16
    Description: Statistical electron parameter correlations associated with high-speed streams are determined with the aim of identifying one or more locally active solar wind heat flux instabilities. Evidence that points toward local regulation of the heat flux at 1 AU is presented, and the results of a search for special signatures expected from the action of the Alfven, magnetosonic, and whistler flux instabilities are discussed. It is shown that under certain conditions, the whistler mode can be active in regulating the heat flux at 1 AU.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; May 1
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  • 57
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    Solar wind speed variations - 1962-1974 (1976)
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    Publication Date: 2011-08-17
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Oct. 1
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  • 58
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    Heating of the solar chromosphere and corona. I - Generalized inhomogeneous wave equation for magnetoacoustic motions (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The generalized inhomogeneous wave equation that governs magnetoacoustic, vortical, and thermal motions in compressible fluids and that is applicable to the problem of heating of the solar chromosphere and corona is obtained. The effects of kinematic and bulk viscosity, heat conduction, Joule dissipation, and magnetic diffusivity are included. Under the usual assumptions, the generalized wave equation reduces to the well-known equations of Lighthill, Kulsrud, Phillips, and others. The major problems encountered in applying Lighthill's (1952) mechanism to sound generation in turbulent media are reviewed for both the subsonic and supersonic cases.
    Keywords: SOLAR PHYSICS
    Type: Astrophysics and Space Science; 43; Aug. 197
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  • 59
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    Doppler noise considered as a function of the signal path integration of electron density (1976)
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    Publication Date: 2011-08-16
    Description: The hypothesis is advanced that observed Doppler noise during solar conjunctions is proportional to total columnar electron content along the signal path. This assumption leads directly to a geometrical model (ISED) for observed Doppler noise which is shown to be in very good agreement with Doppler noise data accumulated during the 1975 Pioneer 10, Pioneer 11 and Helios 1 solar conjunctions. An augmented model is constructed which quantitatively indicates correlation between earth observed sunspot activity and systematic, cyclical deviations from the ISED model.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 159-193
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  • 60
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    The solar spectrum - Wavelengths and identifications from 160 to 770 angstroms (1976)
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 203; Jan. 15
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  • 61
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    On the nonexistence of plane-polarized large amplitude Alfven waves (1976)
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    Publication Date: 2011-08-16
    Description: A theorem is presented which shows that purely Alfvenic plane-polarized large-amplitude disturbances in the solar wind are not possible and will never be observed. The theorem establishes that there is no nontrivial plane-polarized magnetic-field configuration in which the parameter B-squared is constant throughout all space. It is noted, however, that more general nonplanar Alfvenic disturbances may well exist.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Jan. 1
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  • 62
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    Microscale 'Alfven waves' in the solar wind at 1 AU (1976)
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    Publication Date: 2011-08-16
    Description: Data obtained by IMP 1 about interplanetary plasma and magnetic-field fluctuations on a scale of one hour are analyzed. It is found that linearly and circularly polarized Alfven waves were rarely present. Fluctuations having most of the characteristics of large-amplitude 'Alfven waves' and which were observed to be moving away from the sun nearly along the magnetic-field direction are shown not to have been pure transverse Alfven waves since they were accompanied by nonzero fluctuations in the magnetic-field intensity. It is suggested that the fluctuations may have been nonlinear elliptically polarized Alfven waves coupled to the fast mode and moving through a magnetic field that is nonuniform on a scale not exceeding about 0.01 AU.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Jan. 1
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    A shock surface geometry - The February 15-16, 1967, event (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An estimated shape is presented for the surface of the flare-associated interplanetary shock of February 15-16, 1967, as seen in the ecliptic-plane cross section. The estimate is based on observations by Explorer 33 and Pioneers 6 and 7. The estimated shock normal at the Explorer 33 position is obtained by a least-squares shock parameter-fitting procedure for that satellite's data; the shock normal at the Pioneer 7 position is found by using the magnetic coplanarity theorem and magnetic-field data. The average shock speed from the sun to each spacecraft is determined along with the local speed at Explorer 33 and the relations between these speeds and the position of the initiating solar flare. The Explorer 33 shock normal is found to be severely inclined and not typical of interplanetary shocks. It is shown that the curvature of the shock surface in the ecliptic plane near the earth-Pioneer 7 region is consistent with a radius of not more than 0.4 AU.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; Jan. 1
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  • 64
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    Formation of iron sulphide in solar nebula (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Noting that the iron sulfide in the Orgueil carbonaceous meteorite is an Fe-deficient monosulfide (pyrrhotite), it is suggested that such mineral chemistry is inconsistent with equilibrium condensation of the solar nebula and that the course of condensation may have been modified by kinetic effects. The effect of Ni on the reaction between Fe and S to produce FeS is examined, and possible reasons are considered for the fact that the cited meteorite differs in both crystal structure and Ni content from the predictions of equilibrium condensation. It is proposed that sulfide formation in the solar nebula may have been inhibited by sluggish diffusion, so that sulfur began to react with previously condensed troilite to form pyrrhotite. On this basis, observations of the Orgueil sulfides are shown to suggest that the course of solar-system condensation was modified by kinetic effects below about 700 K and that equilibrium may not have been achieved.
    Keywords: SOLAR PHYSICS
    Type: Nature; 259; Jan. 22
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  • 65
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    Kitt Peak 60-cm vacuum telescope (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A major new solar-research telescope conceived and built during a time of budget restraint is described. The observation of magnetic and velocity (circulation) field structure on a synoptic basis and with diffraction-limited resolution is the aim. New optical features include the use of oversize mirrors and windows to avoid thermal edge effects and the placement of the coelostat feed outside the vacuum, mainly for economy. The site selected has prevailing winds that clear thermals from these mirrors. Test data in the form of the system MTF and optical transmission, together with examples of full disk magnetograms and photoheliograms, show present performance capability. Measured MTF indicates a response of 0.2 at 1 sec of arc (whereas diffraction-limited response would be about 0.8). System transmission, including the accompanying spectrograph, is only 2-3% (wavelength 0.44-1.1 microns). Thus, both the optical quality and efficiency are subject to improvement.
    Keywords: SOLAR PHYSICS
    Type: Applied Optics; 15; Jan. 197
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  • 66
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    Solar cycle evolution of high-speed solar wind streams (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Large amplitude high-speed solar wind streams and streams with maximum speeds in excess of 700 km/sec are far more common in years of declining and minimum solar activity than near solar maximum. Further, the broadest solar wind streams observed directly with space probes during the years 1962-1974 occurred near solar minimum in 1974. Changes in the frequency and nature of solar wind stream structures at the orbit of earth appear to be directly related to the long-term evolution of regions of low density in the solar corona.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 207; Aug. 1
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  • 67
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    Electromagnetic instabilities driven by unequal proton beams in the solar wind (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The paper sets forth a numerical investigation of the linear dispersion relation for typical solar wind conditions at 1 AU during those times (high-speed streams) when a secondary beam of protons drifting relative to the main proton component is present. Three beam-driven instabilities were found to occur as the beam drift velocity approaches the Alfven speed: (1) a pure, field-aligned magnetosonic wave that is most important at relatively high beta and/or high beam drift speeds; (2) an oblique magnetosonic wave having highest growth rates 15-30 deg from the magnetic field; and (3) an oblique Alfven wave having maximum growth rates at increasing angle to the magnetic field. The linear growth rates for the field-aligned magnetosonic and the Alfven oblique modes are investigated as a function of relative beam density, varying anisotropic pitch angle distributions for the various components, electron temperature, and electron heat flux.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 81; June 1
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  • 68
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    Low frequency radio observations of the solar wind near the moon (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The RAE-2 lunar orbiter often measures sporadic 20-40 dB intensity increases in the frequency range of 25-110 kHz. Numerous examples of the disappearance of this intense noise during occultations of the sun have been observed. The average position of these occultations coincides with the average location of the plasma cavity above the nightside of the moon. We suggest that the observed high noise levels may be generated near the spacecraft by a disturbed solar wind electron population in the vicinity of the moon.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters; 3; June 197
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  • 69
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    Effect of geometry modifications on effectiveness of slot injection in hypersonic flow (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The study presents wind-tunnel measurements of surface static pressures, equilibrium temperatures, and skin friction downstream of tangential slot injection into a thick turbulent hypersonic boundary layer from two modified slot configurations. The data are compared with results obtained for baseline configurations reported by Cary and Hefner (1970, 1972) to determine whether simple modifications to the slot configuration can produce improved cooling effectiveness and skin friction reduction. The baseline slot configurations are simply modified by thickening the slot lip and by elevating the location of the slot exit above the flat plate. Although the results indicate that simple modifications of the baseline slot configurations can enhance the skin friction reductions obtained with tangential slot injection, slot base drag estimates show that neither of the modifications will lessen the impact of the systems penalties for collecting, ducting, and injecting the slot air.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 14; June 197
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  • 70
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    Turbulence measurements in hypersonic shock-wave boundary-layer interaction flows (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Turbulent intensity and Reynolds shear stress measurements are presented for two nonadiabatic hypersonic shock-wave boundary-layer interaction flows, one with and one without separation. These measurements were obtained using a new hot-wire probe specially designed for heated flows. Comparison of the separated and attached flows shows a significant increase above equilibrium values in the turbulent intensity and shear stress downstream of the interaction region for the attached case, while for the separated case, the turbulent fluxes remain close to equilibrium values. This effect results in substantial differences in turbulence lifetime for the two flows. We propose that these differences are due to a coupling between the turbulent energy and separation bubble unsteadiness, a hypothesis supported by the statistical properties of the turbulent fluctuations.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 14; May 1976
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  • 71
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    Timing of solar cycles by rigid internal rotations (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The so-called 11-year cycle of solar activity is really more complex and contains many periods of greatly different lengths. Periods as long as 178 years and as short as 3.1 years are predicted by a theory based on beats between rigidly rotating, inertially oscillating g-modes inside the sun. Most of the beat periods are then confirmed to about 1 percent accuracy in sunspot observations. Since the agreement is of high statistical significance, one can conclude that approximate alignment of major solar oscillation modes contributes to high solar activity. The theory receives further support when tested against an independent class of observations - the large-scale magnetic sector structure. Predicted rotation rates of at least four solar oscillation modes are detected in the sector data with discrepancies all less than 0.3 percent. As a by-product of these successful fits to observation, the mean rotation of the entire solar mass becomes known. Its rotation frequency is 4.49 by 10 to the -7th power Hz, which is a sidereal period of 25.8 days. Magnetic fields have played no role in calculating the length of any of these solar cycles.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; 205; Apr. 15
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  • 72
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    Comment on the paper 'Solution of one-fluid model equations with short range retarding magnetic forces for the quiet solar wind' by Cuperman and Harten (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SOLAR PHYSICS
    Type: Astrophysics and Space Science; 40; Mar. 197
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  • 73
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    Application of radial-splitters for improved wide-angle diffuser performance in a blowdown tunnel (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Severe flow separation in the 15:1 area-ratio, 38 deg total angle conical diffuser preceding the settling-chamber of an intermittent blowdown wind tunnel was eliminated by the use of a novel radial-splitter arrangement. As a consequence, the operating life of settling-chamber screens was greatly extended and test-section flow steadiness improved, with no penalty in the tunnel running time.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 13; July 197
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  • 74
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    Status and prospects of computational fluid dynamics (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The use and limitations on using computational aerodynamics in approximating inviscid linear, inviscid nonlinear, vicous time averaged, and viscous time dependent flow past airfoils, wings, and aircraft is reviewed. The current status of two- and three-dimensional time averaged Navier-Stokes equation is discussed and possible applications for the 1980 and 1985 to 1990 period is projected for three-dimensional applications.
    Keywords: AERODYNAMICS
    Type: Von Karman Inst. for Fluid Dyn. Computational Fluid Dyn., Vol. 2; 36 p
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  • 75
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    Some recent progress in transonic flow computation (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Although the development of a finite difference relaxation procedure to solve the steady form of equations of motion gave birth to the study of computational transonic aerodynamics and considerable progress has been made using the small disturbance theory, no general analytical solution method yet exists for transonic flows that include three dimensional unsteady, and viscous effects. Two techniques are described which are useful in computational transonic aerodynamics applications. The finite volume method simplifies the application of boundary conditions without introducing the constriction associated with small disturbance theory. Governing equations are solved in a Cartesian coordinate system using a body-oriented and shock-oriented mesh network. Only the volume and surface normal directions of the volume elements must be known. The other method, configuration design by numerical optimization, can be used by aircraft designers to develop configurations that satisfy specific geometric performance constraints. Two examples of airfoil design by numerical optimization are presented.
    Keywords: AERODYNAMICS
    Type: Von Karman Inst. for Fluid Dyn. Computational Fluid Dyn., Vol. 1; 122 p
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  • 76
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    Calculation methods for compressible turbulent boundary layers (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Calculation procedures for non-reacting compressible two- and three-dimensional turbulent boundary layers were reviewed. Integral, transformation and correlation methods, as well as finite difference solutions of the complete boundary layer equations summarized. Alternative numerical solution procedures were examined, and both mean field and mean turbulence field closure models were considered. Physics and related calculation problems peculiar to compressible turbulent boundary layers are described. A catalog of available solution procedures of the finite difference, finite element, and method of weighted residuals genre is included. Influence of compressibility, low Reynolds number, wall blowing, and pressure gradient upon mean field closure constants are reported.
    Keywords: AERODYNAMICS
    Type: Von Karman Inst. for Fluid Dyn. Compressible Turbulent Boundary Layers, Vol. 2; 124 p
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  • 77
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    The large-scale magnetic field in the solar wind (1976)
    In:  CASI
    Details
    Publication Date: 2016-05-14
    Description: A literature review is presented of theoretical models of the interaction of the solar wind and interplanetary magnetic fields. Observations of interplanetary magnetic fields by the IMP and OSO spacecraft are discussed. The causes for cosmic ray variations (Forbush decreases) by the solar wind are examined. The model of Parker is emphasized. This model shows the three dimensional magnetic field lines of the solar wind to have the form of spirals wrapped on cones. It is concluded that an out-of-the-ecliptic solar probe mission would allow the testing and verification of the various theoretical models examined. Diagrams of the various models are shown.
    Keywords: SOLAR PHYSICS
    Type: Proc. of the Symp. on the Study of the Sun and Interplanetary Medium in Three Dimensions; p 143-165
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  • 78
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    USB environment measurements based on full-scale static engine ground tests (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Flow turning parameters, static pressures, surface temperatures, surface fluctuating pressures and acceleration levels were measured in the environment of a full-scale upper surface blowing (USB) propulsive lift test configuration. The test components included a flightworthy CF6-50D engine, nacelle, and USB flap assembly utilized in conjunction with ground verification testing of the USAF YC-14 Advanced Medium STOL Transport propulsion system. Results, based on a preliminary analysis of the data, generally show reasonable agreement with predicted levels based on model data. However, additional detailed analysis is required to confirm the preliminary evaluation, to help delineate certain discrepancies with model data, and to establish a basis for future flight test comparisons.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 479-496
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  • 79
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    NASA participation in the AMST program (1976)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The objectives of the NASA Advanced Medium STOL Transport Experiments Program are discussed and several of the NASA experiments currently implemented and conducted on the YC-14 and YC-15 prototype aircraft are described. Emphasis is placed on experiments related to powered lift aerodynamics and acoustics.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 465-478
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  • 80
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    Investigations of scaling laws for jet impingement (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The statistical properties of tangential flows over surfaces were investigated by two techniques. In one, a laser-Doppler velocimeter was used in a smoke-laden jet to measure one-point statistical properties, including mean velocities, turbulent intensities, intermittencies, autocorrelations, and power spectral densities. In the other technique, free stream and surface pressure probes connected to 1/8 inch microphones were used to obtain single point rms and 1/3 octave pressures, as well as two point cross correlations, the latter being converted to auto spectra, amplitude ratios, phase lags, and coherences. The results of these studies support the vortex model of jets, give some insights into the effects of surface impingement, and confirm that jet diameter and velocity are the scaling parameters for circular jets, while Reynolds number is relatively unimportant.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 445-463
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  • 81
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    Measured and calculated steady aerodynamic loads on a large-scale upper-surface blown model (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Static aerodynamic loads measurements from wind tunnel tests of a full-scale upper surface blown jet flap configuration are presented. The measured loads are compared with calculations using a method for predicting longitudinal aerodynamic characteristics of upper surface blown jet flap configurations.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 415-428
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  • 82
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    Acoustic-loads research for powered-lift configurations (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Data presented from large-scale model tests with jet engines having thrusts of 9 kN (2000 lb) and 36 kN (8000 lb) include acoustic loads for an externally blown wing and flap induced by a TF34 jet engine, an upper surface blown (USB) aircraft model in a wind tunnel, and two USB models in static tests. Comparisons of these results with results from acoustic loads studies on configurations of other sizes are made and the implications of these results on interior noise and acoustic fatigue are discussed.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 429-443
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  • 83
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    Acoustics and aerodynamics of over-the-wing thrust reversers (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: As part of the Quiet Clean Short-Haul Experimental Engine Program, model tests were conducted to determine the effects of thrust reverser geometric parameters on noise and reverse thrust. The acoustic tests used a 1/6 scale model thrust reverser while the aerodynamic performance tests used a 1/12 scale model reverser. Parameters which were varied in both tests include blocker spacing, blocker height, lip angle, and lip length. The impact of these parameters on peak sideline noise and reverse thrust performance is discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 403-414
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  • 84
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    Reverse-thrust technology for variable-pitch fan propulsion systems (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Tests conducted to develop the technology necessary to meet the unique reverse-thrust performance requirements of a variable pitch fan propulsion system are discussed. The losses and distortion associated with the air entering the fan and core compressor from the rear of the engine, the direction of fan blade pitch rotation for best reverse-thrust aeroacoustic performance, and engine response and operating characteristics during forward- to reverse-thrust transients are among the factors studied. The test results of several scale fan models as well as a full-size variable pitch fan engine are summarized. Results show the following: a flared exhaust nozzle makes a good reverse-thrust inlet; acceptable core inlet duct recovery and distortion levels in reverse flow were demonstrated; adequate thrust levels were achieved; forward- to reverse-thrust response time achieved was better than the goal; thrust and noise levels strongly favor reverse through feather pitch; and finally, flight-type inlets make the establishment of reverse flow more difficult.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 387-402
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  • 85
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    Inlet technology for powered-lift aircraft (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The concepts, analytical tools, and experimental data available for designing inlets for powered lift aircraft are discussed. It is shown that inlets can be designed to meet noise, distortion, and cruise drag requirements at the flight and engine operating conditions of a powered lift aircraft. The penalty in pressure recovery for achieving the required noise suppression was 0.3 percent.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 369-385
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  • 86
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    Inlet/nacelle/exhaust system integration for the QCSEE propulsion systems (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The key features of the integrated propulsion systems developed for short haul aircraft are discussed including the high Mach number, fixed geometry, near sonic inlet, the variable area nozzles, thrust reversing systems, and aircraft accessory location. The roles and interplay of each element are considered and comparisons are made with conventional state-of-the-art technology.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 357-367
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  • 87
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    Acoustic design of the QCSEE propulsion systems (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Acoustic design features and techniques employed in the Quiet Clean Short-Haul Experimental Engine (QCSEE) Program are described. The role of jet/flap noise in selecting the engine fan pressure ratio for powered lift propulsion systems is discussed. The QCSEE acoustic design features include a hybrid inlet (near-sonic throat velocity with acoustic treatment); low fan and core pressure ratios; low fan tip speeds; gear-driven fans; high and low frequency stacked core noise treatment; multiple-thickness treatment; bulk absorber treatment; and treatment on the stator vanes. The QCSEE designs represent and anticipated acoustic technology improvement of 12 to 16 PNdb relative to the noise levels of the low-noise engines used on current wide-body commercial jet transport aircraft.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 335-356
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  • 88
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    Overview of the QCSEE program (1976)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Externally blown flap and upper surface blown flap powered lift concepts were investigated in the Quiet Clean Short-Haul Experimental Engine Program and briefly discussed along with propulsion system requirements. Noise limits, emission standards, thrust requirements, and thrust-to-weight ratios are among the factors considered.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 325-333
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  • 89
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    EBF noise reduction through nozzle/flap positioning (1976)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Results are presented of an experimental and analytical study of the dependence of externally blown flap (EBF) noise on the relative position and shape of engine exhaust nozzle. Tests, conducted on a 1/15 scale model of a triple-slotted EBF system, indicate that a significant reduction (of up to 10 to 15 db for no forward speed case and of up to 5 to 10 db for forward speed case) is possible in the low frequency (around 63 Hz) region of the noise spectrum of the full scale device for small nozzle/flap separation distances. The overall acoustic performance, measured in PNdb, does not exhibit significant reductions. The analysis of the EBF noise is carried out for two limiting airfoil in a free jet. The analytical results also suggest that low frequency noise can be reduced by placing the nozzle close to the flow turning elements.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 307-324
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  • 90
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    USB noise reduction by nozzle and flap modifications (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The development of concepts for reducing upper surface blown flap noise at the source through flap modifications and special nozzles is reviewed. In particular, recent results obtained on the aerodynamic and acoustic performance of flaps with porous surfaces near the trailing edge and multi-slotted nozzles are reviewed. Considerable reduction (6-10 db) of the characteristic low frequency peak is shown. The aerodynamic performance is compared with conventional systems, and prospects for future improvements are discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 283-305
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  • 91
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    Analytical modeling of under-the-wing externally blown flap powered-lift noise (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The sound field produced by the interaction of a subsonic jet with a large-scale model of the under the wing externally blown flap in an approach attitude was analyzed. The analysis was performed to obtain a better understanding of the dominant noise sources and the mechanisms governing the peak sound pressure level frequencies of the broadband spectra. An analytical expression is derived which incorporates two available theories and experimental data; the expression predicts the sound field along a circular arc of approximately 120 deg measured from the upstream jet axis in the fly-over plane. The analysis compares favorably with test results obtained from two large-scale models, one using cold air from a conical nozzle and the other using hot gas from a TF-34 turbofan engine having a conical exhaust nozzle with a 12 lobe internal forced mixer. The frequency at which the peak sound pressure level occurs appears to be governed by a phenomenon which produces periodic formation and shedding of large-scale turbulence structures from the nozzle lip.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 263-282
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  • 92
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    USB flow characteristics related to noise generation (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The effects of nozzle and flap geometry on upper surface blown flow field characteristics related to noise generation were examined experimentally using static models. Flow attachment and spreading characteristics were observed using flow visualization techniques. Velocity and turbulence profiles in the trailing edge wake were measured using hot-wire anemometry, and the effects of the geometric variables on peak velocity and turbulence intensity were determined. It is shown that peak trailing edge velocity is a function of the ratio of flow length to modified hydraulic diameter.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 213-226
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  • 93
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    Effects of nozzle design and power on cruise drag for upper-surface-blowing aircraft (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A high speed wind tunnel investigation was conducted on a series of upper surface blowing nozzles with D-shaped exits installed on a representative short haul aircraft model. Both two and four engine configurations were investigated. Powered engine simulators were used to properly represent nacelle flows. Large differences in cruise drag penalties associated with the various nozzle designs were seen. Some geometric parameters influencing nozzle cruise drag are identified.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 183-196
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  • 94
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    Distributed upper-surface blowing concept (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A low speed investigation was conducted in the Langley V/STOL tunnel to determine the powered lift aerodynamic performance of a distributed upper surface blown propulsive lift transport model. The model used blowing slots across the span of the wing to produce a thin jet efflux near the leading edge and at the knee of the trailing edge flap (internally blown jet flap). Results indicate that these concepts have both good propulsive related lift and low drag due to lift characteristics because of uniform spanwise propulsive thrust. The leading edge blowing concept provides low speed lift characteristics which are competitive with the flap-hinge-line blowing concept and does not require additional leading edge treatment for prevention of abrupt stall.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 159-164
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  • 95
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    Aerodynamic characteristics in ground proximity (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Results from recent investigations in the Langley V/STOL tunnel of an externally blown flap and an upper surface blown flap configuration in ground proximity are presented. Comparisons of longitudinal aerodynamic characteristics indicate that in ground proximity, drag is reduced for both configurations, but changes in lift are configuration dependent. Steady state analyses of the landing approach indicate an increase in flight path angle for both configurations in ground proximity because of the drag reduction. Dynamic analyses with a fixed-base simulator indicate that the resultant flight path during landing approach is dependent on the initial flight path angle and the control technique used.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 145-158
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  • 96
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    Some measurements of an EBF powered-lift wake (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Results from a wind tunnel investigation in which velocity vector measurements were obtained in the near wake of an externally blown flap powered lift configuration were analyzed. These measurements were used to develop spanwise distributions for the momentum strength and location of the engine exhaust stream tube with the results used as input parameters to one jet flap analytical method. It is shown that a comparison of the momentum coefficients obtained from forward speed wake surveys with the predicted values from static force data results in a good correlation, which verifies the use of the flap thrust recovery factor as a means of predicting the momentum strength at the flap trailing edge. Also, when wake survey distributions of momentum strength and direction are used as input parameters to one analytical jet flap method, the results show reasonable agreement between the experimental data and analytical results.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 135-143
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  • 97
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    Externally blown flap impingement parameters (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The performance of two externally blown flap (EBF) wind tunnel models was compared with an engine exhaust flap impingement correlation parameter. One model was a four engine EBF triple slotted flap transport. Isolated engine wake surveys were conducted to define the wake properties of five separate engine configurations for which performance data were available. The other model was a two engine EBF transport for which the engine wake properties were estimated. The correlation parameter was a function of engine exhaust dynamic pressure at the flap location, area of engine exhaust flap impingement, total exhaust area at the flap location, and engine thrust. The distribution of dynamic pressure for the first model was measured; however, the distribution for the second model was assumed to be uniform.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Powered-Lift Aerodyn. and Acoustics; p 119-134
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  • 98
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    Application of powered-lift concepts for improved cruise efficiency of long-range aircraft (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Results of studies conducted to explore the use of powered lift concepts for improved low speed performance of long range subsonic and supersonic cruise vehicles are summarized. It is indicated that powered lift can provide significant improvements in low speed performance, as well as substantial increases in cruise efficiency and range for both subsonic and supersonic cruise configurations.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 89-101
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  • 99
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    Summary of low-speed aerodynamic characteristics of upper-surface-blown jet-flap configurations (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The results of recent wind tunnel investigations to provide fundamental information on the upper surface blown (USB) jet flap concept demonstrated that the USB concept provides good high-lift performance. It is shown that the low speed performance is dependent upon the jet turning angle and turning efficiency and on the use of proper leading and trailing edge treatment to prevent premature flow separation. The best means of achieving good turning performance in any particular USB application must be determined from overall operational considerations in which high speed performance, structures and noise, as well as low speed performance, are evaluated. The large diving moments generated at high lift coefficients can be trimmed satisfactorily with a large, conventional horizontal tail; a high tail position is best from longitudinal stability considerations. Large rolling and yawing moments are introduced with the loss of an engine, but these moments can be trimmed satisfactorily through the use of asymmetrical boundary layer control and through the use of spoiler and rudder deflection as needed.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 63-87
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  • 100
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    Results of static tests of a 1/4 scale model of the Boeing YC-14 powered-lift system (1976)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: One quarter scale static ground tests of the Boeing YC-14 powered lift system were conducted for correlation with full scale test results. The 1/4 scale model utilized a JT-15D turbofan engine to represent the CF6-50D engine employed on the YC-14 advanced medium STOL transport prototype aircraft. The tests included evaluation of static turning performance, static surface pressure and temperature distributions, fluctuating loads, and accelerations of portions of the wing, flaps, and fuselage. Results are presented for the landing flap configuration over an appropriate range of fan pressure ratio as affected by several variables including ground height and vortex generator modifications. Static turning angles of the order of 60 deg were obtained. The highest surface pressures and temperatures were concentrated over the upper surface of the flaps in the region immediately aft of the upper surface blown nozzle.
    Keywords: AERODYNAMICS
    Type: Powered-Lift Aerodyn. and Acoustics; p 45-62
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