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  • 1
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    Turbulence models for compressible boundary layers (1994)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: It is shown that to satisfy the general accepted compressible law of the wall derived from the Van Driest transformation, turbulence modeling coefficients must actually be functions of density gradients. The transformed velocity profiles obtained by using standard turbulence model constants have too small a value of the effective von Karman constant kappa in the log-law region (inner layer). Thus, if the model is otherwise accurate, the wake component is overpredicted and the predicted skin friction is lower than the expected value.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 32; 4; p. 735-740
    Format: text
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  • 2
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    Skin friction and velocity profile family for compressible turbulent boundary layers (1993)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: The paper presents a general approach to constructing mean velocity profiles for compressible turbulent boundary layers with isothermal or adiabatic walls. The theory is based on a density-weighted transformation that allows the extension of the incompressible similarity laws of the wall to the compressible regions. The velocity profile family is compared to a range of experimental data, and excellent agreement is obtained. A self-consistent skin friction law, which satisfies the proposed velocity profile family, is derived and compared with the well-known Van Driest II theory for boundary layers in zero pressure gradient. The results are found to be at least as good as those obtained by using the Van Driest II transformation.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 31; 9; p. 1600-1604.
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  • 3
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    Turbulence modeling for hypersonic flows (1992)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Turbulence modeling for high-speed compressible flows is described and discussed. Starting with the compressible Navier-Stokes equations, methods of statistical averaging are described by means of which the Reynolds-averaged Navier-Stokes equations are developed. Unknown averages in these equations are approximated using various closure concepts. Zero-, one-, and two-equation eddy viscosity models, algebraic stress models, and Reynolds stress transport models are discussed. Computations of supersonic and hypersonic flows obtained using several of the models are discussed and compared with experimental results. Specific examples include attached boundary-layer flows, shock-wave boundary-layer interactions, and compressible shear layers. From these examples, conclusions regarding the status of modeling and recommendations for future studies are discussed.
    Keywords: AERODYNAMICS
    Type: In: Advances in hypersonics. Vol. 2 - Modeling hypersonic flows (A94-10759 01-02); p. 1-43.
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  • 4
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    Preliminary numerical investigation of sonic boom at threshold Mach numbers (1971)
    In:  CASI
    Details
    Publication Date: 2005-11-27
    Description: Mathematical model for supersonic aircraft Mach number threshold operation for atmospheric reflection of sonic boom
    Keywords: AIRCRAFT
    Type: 3D CONF. ON SONIC BOOM RES. 1971; P 181-191
    Format: text
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  • 5
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    An experimental and numerical investigation of shock wave induced turbulent boundary layer separation at hypersonic speeds (1975)
    In:  CASI
    Details
    Publication Date: 2011-10-14
    Description: A thoroughly documented experiment is reported that was specifically designed to test and guide computations of the interaction of an impinging shock wave with a turbulent boundary layer. Detailed mean flow field and surface data are presented for two shock strengths which resulted in attached and separated flows, respectively. Numerical computations are used to illustrate the dependence of the computations on the particulars of the turbulence models. Models appropriate for zero pressure gradient flows predicted the overall features of the flow fields, but were deficient in predicting many of the details of the interaction regions. Improvements to the turbulence model parameters were sought through a combination of detailed data analysis and computer simulations which tested the sensitivity of the solutions to model parameter changes. Computer simulations using these improvements are presented and discussed.
    Keywords: AERODYNAMICS
    Type: AGARD Flow Separation; 13 p
    Format: text
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  • 6
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    Improvements to a nonequilibrium algebraic turbulence model (1990)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: It has been noted that while the nonequilibrium turbulence model of Johnson and King (1985, 1987) performed significantly better than alternative methods, differences between predicted and observed shock locations for certain weak interactions are produced due to a defficiency in the model's inner eddy viscosity formulation. A novel formulation for the model is presented which removes this deficiency, while satisfying the law of the wall for adverse pressure-gradient conditions better than either the original formulation or mixing-length theory.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 28; 2000-200
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  • 7
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    Numerical simulation and comparison with experiment for self-excited oscillations in a diffuser flow (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 25; 936-943
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  • 8
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    Turbulent properties of axisymmetric shock-wave/boundary-layer interaction flows (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A combined experimental and computational investigation of an axisymmetric turbulent shock-wave boundary-layer interaction flow is presented. Experimental measurements include both mean and fluctuating data obtained by LDV techniques and identify large scale unsteady motions associated with shock induced separation. Computations using the compressible Navier-Stokes equations, and a two-equation turbulence model are in relatively good agreement with experimental measurements. It is found that the large scale unsteady motions do not appear to have a critical impact on the ability to compute the mean properties of the flows investigated in this paper.
    Keywords: AERODYNAMICS
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  • 9
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    Numerical simulations of unsteady transonic flow in diffusers (1984)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2346, Accession no. A82-31959
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 22; 1139-114
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  • 10
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    Implicit upwind methods for the compressible Navier-Stokes equations (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 23; 374-380
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