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Turbulence Modeling For High Speed Compressible Flows
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Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781792954474 Total Pages :28 pages Book Rating :4.9/5 (544 download)
Book Synopsis Turbulence Modeling for High Speed Compressible Flows by : National Aeronautics and Space Adm Nasa
Download or read book Turbulence Modeling for High Speed Compressible Flows written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-04 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The following grant objectives were delineated in the proposal to NASA: to offer course work in computational fluid dynamics (CFD) and related areas to enable mechanical engineering students at North Carolina A&T State University (N.C. A&TSU) to pursue M.S. studies in CFD, and to enable students and faculty to engage in research in high speed compressible flows. Since no CFD-related activity existed at N.C. A&TSU before the start of the NASA grant period, training of students in the CFD area and initiation of research in high speed compressible flows were proposed as the key aspects of the project. To that end, graduate level courses in CFD, boundary layer theory, and fluid dynamics were offered. This effort included initiating a CFD course for graduate students. Also, research work was performed on studying compressibility effects in high speed flows. Specifically, a modified compressible dissipation model, which included a fourth order turbulent Mach number term, was incorporated into the SPARK code and verified for the air-air mixing layer case. The results obtained for this case were compared with a wide variety of experimental data to discern the trends in the mixing layer growth rates with varying convective Mach numbers. Comparison of the predictions of the study with the results of several analytical models was also carried out. The details of the research study are described in the publication entitled 'Compressibility Effects in Modeling Turbulent High Speed Mixing Layers, ' which is attached to this report. Chandra, Suresh NASA-CR-194547, NAS 1.26:194547 NAG1-1287...
Book Synopsis Compressibility, Turbulence and High Speed Flow by : Thomas B. Gatski
Download or read book Compressibility, Turbulence and High Speed Flow written by Thomas B. Gatski and published by Academic Press. This book was released on 2013-03-05 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compressibility, Turbulence and High Speed Flow introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range, through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. The book provides the reader with the necessary background and current trends in the theoretical and experimental aspects of compressible turbulent flows and compressible turbulence. Detailed derivations of the pertinent equations describing the motion of such turbulent flows is provided and an extensive discussion of the various approaches used in predicting both free shear and wall bounded flows is presented. Experimental measurement techniques common to the compressible flow regime are introduced with particular emphasis on the unique challenges presented by high speed flows. Both experimental and numerical simulation work is supplied throughout to provide the reader with an overall perspective of current trends. An introduction to current techniques in compressible turbulent flow analysis An approach that enables engineers to identify and solve complex compressible flow challenges Prediction methodologies, including the Reynolds-averaged Navier Stokes (RANS) method, scale filtered methods and direct numerical simulation (DNS) Current strategies focusing on compressible flow control
Book Synopsis Compressibility, Turbulence and High Speed Flow by : Thomas B. Gatski
Download or read book Compressibility, Turbulence and High Speed Flow written by Thomas B. Gatski and published by Elsevier. This book was released on 2009-02-27 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. For the computation of turbulent compressible flows, current methods of averaging and filtering are presented so that the reader is exposed to a consistent development of applicable equation sets for both the mean or resolved fields as well as the transport equations for the turbulent stress field. For the measurement of turbulent compressible flows, current techniques ranging from hot-wire anemometry to PIV are evaluated and limitations assessed. Characterizing dynamic features of free shear flows, including jets, mixing layers and wakes, and wall-bounded flows, including shock-turbulence and shock boundary-layer interactions, obtained from computations, experiments and simulations are discussed. Describes prediction methodologies including the Reynolds-averaged Navier Stokes (RANS) method, scale filtered methods and direct numerical simulation (DNS) Presents current measurement and data analysis techniques Discusses the linkage between experimental and computational results necessary for validation of numerical predictions Meshes the varied results of computational and experimental studies in both free and wall-bounded flows to provide an overall current view of the field
Book Synopsis Turbulence Model Assessment for High Speed Compressible Flows by : Vijaykumar Gopalakrishnan
Download or read book Turbulence Model Assessment for High Speed Compressible Flows written by Vijaykumar Gopalakrishnan and published by . This book was released on 2005 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling turbulence is an important aspect of high speed flows from a solution accuracy point of view. This present research work focuses on the assessment of different turbulence models in predicting shock-wave turbulent boundary layer interactions induced by a compression ramp. This case is unique due to the fact that unlike earlier works on this topic, it focuses on non-separating boundary layer. Five turbulence models were assessed and are compared according to the prediction of pressure profiles, skin friction coefficient profiles and boundary layer velocity profiles.
Book Synopsis Turbulence and Transition Modeling for High-speed Flows by : United States. National Aeronautics and Space Administration
Download or read book Turbulence and Transition Modeling for High-speed Flows written by United States. National Aeronautics and Space Administration and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722919115 Total Pages :50 pages Book Rating :4.9/5 (191 download)
Book Synopsis Turbulence Modeling for Hypersonic Flows by : National Aeronautics and Space Administration (NASA)
Download or read book Turbulence Modeling for Hypersonic Flows written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-15 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. Marvin, J. G. and Coakley, T. J. Ames Research Center RTOP 505-60-11...
Book Synopsis Application of a Two-equation Turbulence Model for High Speed Compressible Flows Using Unstructured Grids by : Gururaja R. Vemaganti
Download or read book Application of a Two-equation Turbulence Model for High Speed Compressible Flows Using Unstructured Grids written by Gururaja R. Vemaganti and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Turbulence Modeling for Compressible Shear Flows by : Carlos Arturo Gomez Elizondo
Download or read book Turbulence Modeling for Compressible Shear Flows written by Carlos Arturo Gomez Elizondo and published by . This book was released on 2013 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compressibility profoundly affects many aspects of turbulence in high-speed flows - most notably stability characteristics, anisotropy, kinetic-potential energy interchange and spectral cascade rate. Many of the features observed in compressible flows are due to the changing nature of pressure. Whereas for incompressible flows pressure merely serves to enforce incompressibility, in compressible flows pressure becomes a thermodynamic variable that introduces a strong coupling between energy, state, and momentum equations. Closure models that attempt to address compressibility effects must begin their development from sound first-principles related to the changing nature of pressure as a flow goes from incompressible to compressible regime. In this thesis, a unified framework is developed for modeling pressure-related compressibility effects by characterizing the role and action of pressure at different speed regimes. Rapid distortion theory is used to examine the physical connection between the various compressibility effects leading to model form suggestions for the pressure-strain correlation, pressure-dilatation and dissipation evolution equation. The pressure-strain correlation closure coefficients are established using fixed point analysis by requiring consistency between model and direct numerical simulation asymptotic behavior in compressible homogeneous shear flow. The closure models are employed to compute high-speed mixing-layers and boundary layers in a differential Reynolds stress modeling solver. The self-similar mixing-layer profile, increased Reynolds stress anisotropy and diminished mixing-layer growth rates with increasing relative Mach number are all well captured. High-speed boundary layer results are also adequately replicated even without the use of advanced thermal-flux models or low Reynolds number corrections. To reduce the computational burden required for differential Reynolds stress calculations, the present compressible pressure-strain correlation model is incorporated into the algebraic modeling framework. The resulting closure is fully explicit, physically realizable, and is a function of mean flow strain rate, rotation rate, turbulent kinetic energy, dissipation rate, and gradient Mach number. The new algebraic model is validated with direct numerical simulations of homogeneous shear flow and experimental data of high-speed mixing-layers. Homogeneous shear flow calculations show that the model captures the asymptotic behavior of direct numerical simulations quite well. Calculations of plane supersonic mixing-layers are performed and comparison with experimental data shows good agreement. Therefore the algebraic model may serve as a surrogate for the more computationally expensive differential Reynolds stress model for flows that permit the weak-equilibrium simplification. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148160
Book Synopsis A Combined Large-Eddy Simulation and Time-Dependent RANS Capability for High-Speed Compressible Flows by :
Download or read book A Combined Large-Eddy Simulation and Time-Dependent RANS Capability for High-Speed Compressible Flows written by and published by . This book was released on 1997 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: An entirely new approach to the large-eddy simulation (LES) of high-speed compressible turbulent flows is presented. Subgrid scale stress models are proposed that are dimensionless functions of the computational mesh size times a Reynolds stress model. This allows a DNS to go continuously to an LES and then a Reynolds-averaged Navier-Stokes (RANS) computation as the mesh becomes successively more coarse or the Reynolds number becomes much larger. Here, the level of discretization is parameterized by the non-dimensional ratio of the computational mesh size to the Kolmogorov length scale. The Reynolds stress model is based on a state-of-the-art two-equation model whose enhanced performance is documented in detail in a variety of benchmark flows. It contains many of the most recent advances in compressible turbulence modeling. Applications to the high-speed aerodynamic flows of technological importance are briefly discussed.
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781728924809 Total Pages :30 pages Book Rating :4.9/5 (248 download)
Book Synopsis On the Basic Equations for the Second-Order Modeling of Compressible Turbulence by : National Aeronautics and Space Adm Nasa
Download or read book On the Basic Equations for the Second-Order Modeling of Compressible Turbulence written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-18 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Equations for the mean and turbulent quantities for compressible turbulent flows are derived. Both the conventional Reynolds average and the mass-weighted, Favre average were employed to decompose the flow variable into a mean and a turbulent quality. These equations are to be used later in developing second order Reynolds stress models for high speed compressible flows. A few recent advances in modeling some of the terms in the equations due to compressibility effects are also summarized. Liou, W. W. and Shih, T.-H. Glenn Research Center NASA ORDER C-99066-G; RTOP 505-62-21
Book Synopsis Turbulence and Transition Modeling for High-speed Flows by :
Download or read book Turbulence and Transition Modeling for High-speed Flows written by and published by . This book was released on 1993 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Simulation of Shock/Turbulent Boundary Layer Interaction by : National Aeronautics and Space Adm Nasa
Download or read book Numerical Simulation of Shock/Turbulent Boundary Layer Interaction written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most flows of aerodynamic interest are compressible and turbulent. However, our present knowledge on the structures and mechanisms of turbulence is mostly based on incompressible flows. In the present work, compressibility effects in turbulent, high-speed, boundary layer flows are systematically investigated using the Direct Numerical Simulation (DNS) approach. Three-dimensional, time-dependent, fully nonlinear, compressible Navier-Stokes equations were numerically integrated by high-order finite-difference methods; no modeling for turbulence is used during the solution because the available resolution is sufficient to capture the relevant scales. The boundary layer problem deals with fully-turbulent compressible flows over flat geometries. Apart from its practical relevance to technological flows, turbulent compressible boundary layer flow is the simplest experimentally realizable turbulent compressible flow. Still, measuring difficulties prohibit a detailed experimental description of the flow, especially in the near-wall region. DNS studies provide a viable means to probe the physics of compressible turbulence in this region. The focus of this work is to explore the paths of energy transfer through which compressible turbulence is sustained. The structural similarities and differences between the incompressible and compressible turbulence are also investigated. The energy flow patterns or energy cascades are found to be directly related to the evolution of vortical structures which are generated in the near-wall region. Near-wall structures, and mechanisms which are not readily accessible through physical experiments are analyzed and their critical role on the evolution and the behavior of the flow is documented extensively. Biringen, Sedat and Hatay, Ferhat F. Unspecified Center NAG1-1472...
Book Synopsis On the Basic Equations for the Second-order Modeling of Compressible Turbulence by : W. W. Liou
Download or read book On the Basic Equations for the Second-order Modeling of Compressible Turbulence written by W. W. Liou and published by . This book was released on 1991 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722009663 Total Pages :44 pages Book Rating :4.0/5 (96 download)
Book Synopsis A Near-Wall Two-Equation Model for Compressible Turbulent Flows by : National Aeronautics and Space Administration (NASA)
Download or read book A Near-Wall Two-Equation Model for Compressible Turbulent Flows written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-28 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A near-wall two-equation turbulence model of the K - epsilon type is developed for the description of high-speed compressible flows. The Favre-averaged equations of motion are solved in conjunction with modeled transport equations for the turbulent kinetic energy and solenoidal dissipation wherein a variable density extension of the asymptotically consistent near-wall model of So and co-workers is supplemented with new dilatational models. The resulting compressible two-equation model is tested in the supersonic flat plate boundary layer - with an adiabatic wall and with wall cooling - for Mach numbers as large as 10. Direct comparisons of the predictions of the new model with raw experimental data and with results from the K - omega model indicate that it performs well for a wide range of Mach numbers. The surprising finding is that the Morkovin hypothesis, where turbulent dilatational terms are neglected, works well at high Mach numbers, provided that the near wall model is asymptotically consistent. Instances where the model predictions deviate from the experiments appear to be attributable to the assumption of constant turbulent Prandtl number - a deficiency that will be addressed in a future paper. Zhang, H. S. and So, R. M. C. and Speziale, C. G. and Lai, Y. G. Unspecified Center NAS1-18605; RTOP 505-90-52-01...
Book Synopsis A New Approach to the Large-Eddy Simulation of High-Speed Compressible Flows by :
Download or read book A New Approach to the Large-Eddy Simulation of High-Speed Compressible Flows written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: All entirely new approach to the large-eddy simulation (LES) of high speed compressible turbulent flows is presented. In this new approach to large-eddy simulations, subgrid scale stress models go continuously to Reynolds stress models in the coarse mesh/infinite Reynolds number limit, where a Reynolds stress calculation (RANS) is done in parallel with the LES to get an estimate of the Kolmogorov length scale. Hence, this formally constitutes a combined LES/time dependent RANS capability. Here, the Reynolds stress model that is recovered in the coarse mesh limit has a dependence on rotational strains through strain-dependent coefficients as well as through anisotropic eddy viscosity terms which are usually neglected in subgrid scale models. Unlike in existing subgrid scale models, this new model has the correct dependence on the mesh size through the dimensionless ratio of the computational mesh size to the Kolmogorov length scale. It is this ratio that determines how well-resolved a computation is in the numerical simulation of turbulence and should be used to parameterize subgid scale models. Use is made of the Morkovin hypothesis in the formulation of compressible subgrid scale models. This allows for the description of supersonic turbulent flows provided that they are not in the hypersonic flow regime. A critical assessment of this new approach is provided along with a discussion of traditional approaches and the prospects for future applications to the high-speed compressible flows of technological importance.
Book Synopsis A Near-wall Two-equation Model for Compressible Turbulent Flows by : Institute for Computer Applications in Science and Engineering
Download or read book A Near-wall Two-equation Model for Compressible Turbulent Flows written by Institute for Computer Applications in Science and Engineering and published by . This book was released on 1991 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Boundary Layer Flows by : Vallampati Ramachandra Prasad
Download or read book Boundary Layer Flows written by Vallampati Ramachandra Prasad and published by BoD – Books on Demand. This book was released on 2020-01-22 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts in the field, this book, "Boundary Layer Flows - Theory, Applications, and Numerical Methods" provides readers with the opportunity to explore its theoretical and experimental studies and their importance to the nonlinear theory of boundary layer flows, the theory of heat and mass transfer, and the dynamics of fluid. With the theory's importance for a wide variety of applications, applied mathematicians, scientists, and engineers - especially those in fluid dynamics - along with engineers of aeronautics, will undoubtedly welcome this authoritative, up-to-date book.
