ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (253)
  • FLUID MECHANICS AND HEAT TRANSFER  (140)
  • STRUCTURAL MECHANICS  (113)
  • Life and Medical Sciences
  • 1990-1994  (143)
  • 1980-1984  (110)
  • 1940-1944
  • 1935-1939
  • 1915-1919
  • 1880-1889
  • 1990  (143)
  • 1984  (110)
  • 1939
Collection
Source
Keywords
Years
  • 1990-1994  (143)
  • 1980-1984  (110)
  • 1940-1944
  • 1935-1939
  • 1915-1919
    • +
Year
  • 1
    facet.materialart.
    Unknown
    Numerical simulation of solidification in a horizontal cylindrical annulus charged with an aqueous salt solution (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: A computational study of solidification of a binary Na2CO3 solution in a horizontal cylindrical annulus is performed using a continuum formulation with a control-volume based, finite-difference scheme. The initial conditions were selected to facilitate the study of counter thermal and solutal convection, accompanied by extensive mushy region growth. Numerical results are compared with experimental data with mixed success. Qualitative agreement is obtained for the overall solidification process and associated physical phenomena. However, the plume thickness calculated for the solutally-driven convective upflow is substantially smaller than the observed value. Evolution of double-diffusive layers is predicted, but over a time scale much smaller than that observed experimentally. Good agreement is obtained between predicted and measured results for solid growth, but the mushy region thickness is significantly overpredicted.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer (ISSN 0017-9310); 33; 367-380
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Low order dynamical models for mixing layers (1990)
    In:  CASI
    Details
    Publication Date: 2013-08-29
    Description: The goal of this project was to investigate the feasibility of developing useful low order dynamical systems to allow one to determine cheaply the effect of various initial conditions on the evolution of mixing layers. A mathematically rigorous approach for a time evolving base flow as found in a mixing layer seems to be the singular value decomposition of the linear operator transforming some initial perturbations into the solution at a given later time. Unfortunately, this is very costly, if at all feasible, and only deals with the linear evolution of a disturbance. A different approach based on weakly nonlinear analysis was attempted, but numerous difficulties were encountered. Several formulations were proposed which may be ill-posed. The reasons for this possible failure of the attempted approach is related to the fundamental limitations of weakly nonlinear analysis. The clarification of these issues is attempted in this report.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Stanford Univ., Studying Turbulence Using Numerical Simulation Databases. 3: Proceedings of the 1990 Summer Program; p 205-210
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Exponential approximations in optimal design (1990)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: One-point and two-point exponential functions have been developed and proved to be very effective approximations of structural response. The exponential has been compared to the linear, reciprocal and quadratic fit methods. Four test problems in structural analysis have been selected. The use of such approximations is attractive in structural optimization to reduce the numbers of exact analyses which involve computationally expensive finite element analysis.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA, Langley Research Center, Research in Structures, Structural Dynamics and Materials, 1990; p 137-150
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    One-dimensional hybrid continuum/particle simulation approach for rarefied hypersonic flows (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A hybrid numerical technique, based on local application of continuum and particle methods, is applied to the one-dimensional normal shock structure in a monatomic gas. The methods are coupled iteratively via a flux boundary condition in a region where both are applicable. The validity of each method through the shock structure is quantified. The physical and numerical aspects of coupling are discussed and a variety of coupling methods are assessed. Results are presented to show the improvement in computational efficiency available via the hybrid approach.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA PAPER 90-1690
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Turbulence characteristics of an axisymmetric reacting flow (1984)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Turbulent sudden expansion flows are of significant theoretical and practical importance. Such flows have been the subject of extensive analytical and experimental study for decades, but many issues are still unresolved. Detailed information on reacting sudden expansion flows is very limited, since suitable measurement techniques have only been available in recent years. The present study of reacting flow in an axisymmetric sudden expansion was initiated under NASA support in December 1983. It is an extension of a reacting flow program which has been carried out with Air Force support under Contract F33615-81-K-2003. Since the present effort has just begun, results are not yet available. Therefore a brief overview of results from the Air Force program will be presented to indicate the basis for the work to be carried out.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 189-198
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Transient vibration test criteria for spacecraft hardware (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: Transient vibration test criteria, developed for spacecraft hardware, provide a test rationale to verify the capability of the hardware to withstand the low and mid frequency transient vibration environments induced by launch vehicle events. A test method, consisting of a series of discrete frequency, limited cycle, modulated sine wave pulses, was developed to avoid the slow swept sine drawbacks, yet provide a repeatable test that would excite all frequencies. The shape of the waveform is that of the classic response of the mass of a one degree of freedom system when it is base-excited by an exponentially decayed sine wave transient. Criteria were developed to define pulse amplitudes, shapes, and center frequencies from spacecraft loads analyses. Test tolerance criteria were also developed and specified. The transient vibration test criteria were implemented on spacecraft flight hardware and provided a more realistic test simulation (i.e., less conservative) for qualification of spacecraft hardware without risk of undertest.
    Keywords: STRUCTURAL MECHANICS
    Type: Shock and Vibration Information Center The Shock and Vibration Bull. 54, Pt. 3; p 99-110
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Extension of transonic flow computational concepts in the analysis of cavitated bearings (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An analogy between the mathematical modeling of transonic potential flow and the flow in a cavitating bearing is described. Based on the similarities, characteristics of the cavitated region and jump conditions across the film reformation and rupture fronts are developed using the method of weak solutions. The mathematical analogy is extended by utilizing a few computational concepts of transonic flow to numerically model the cavitating bearing. Methods of shock fitting and shock capturing are discussed. Various procedures used in transonic flow computations are adapted to bearing cavitation applications, for example, type differencing, grid transformation, an approximate factorization technique, and Newton's iteration method. These concepts have proved to be successful and have vastly improved the efficiency of numerical modeling of cavitated bearings.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ASME PAPER 90-TRIB-40
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    A laser Doppler velocimeter approach for near-wall three-dimensional turbulence measurements (1990)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A near-wall laser Doppler velocimeter approach is described that relies on a beam-turning probe which makes possible the direct measurement of the crossflow velocity at a grazing incident and the placement of optical components close to the flow region of interest regardless of test facility size. Other important elements of the approach are the use of digital frequency processing, an optically smooth measurement surface, and observation of the sensing volume at 90 degrees. The combination was found to dramatically reduce noise-in-signal effects caused by surface light scattering. Turbulent boundary-layer data to within 20 microns (y(sup+) approximately equal to 1) of the surface are presented which illustrate the potential of the approach.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-TM-102841 , A-90207 , NAS 1.15:102841 , International Symposium on Application of Laser Techniques in Fluid Mechanics; Jul 09, 1990 - Jul 12, 1990; Lisbon; Portugal
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    The width-tapered double cantilever beam for interlaminar fracture testing (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The width-tapered double-cantilever-beam (WTDCB) specimen configuration used to determine the Mode-I interlaminar fracture energy (IFE) of composites has special advantages for routine development work and for quality-assurance purposes. These advantages come primarily from the simplicity of testing and the fact that the specimen is designed for constant change in compliance with crack length, so that the computation of Mode-I IFE is independent of crack length. In this paper, a simplified technique for fabrication and testing WTDCB specimens is described. Also presented are the effects of fiber orientation and specimen dimensions, a comparison of data obtained using the WTDCB specimens and other specimen geometries, and comparison of data obtained at different laboratories. It is concluded that the WTDCB gives interlaminar Mode-I IFE essentially equal to other type specimens, and that it can be used for rapid screening in resin-development work and for quality assurance of composite materials.
    Keywords: STRUCTURAL MECHANICS
    Type: Technology vectors; Apr 03, 1984 - Apr 05, 1984; Reno, NV
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    A collision-selection rule for a particle simulation method suited to vector computers (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: A theory is developed for a selection rule governing collisions in a particle simulation of rarefied gas-dynamic flows. The selection rule leads to an algorithmic form highly compatible with fine grain parallel decomposition, allowing for efficient utilization of supercomputers having vector or massively parallel single instruction multiple data architectures. A comparison of shock-wave profiles obtained using both the selection rule and Bird's direct simulation Monte Carlo (DSMC) method show excellent agreement. The equation on which the selection rule is based is shown to be directly related to the time-counter procedure in the DSMC method. The results of several example simulations of representative rarefied flows are presented, for which the number of particles used ranged from 10 to the 6th to 10 to the 7th demonstrating the greatly improved computational efficiency of the method.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids A (ISSN 0899-8213); 2; 1248-125
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...