Evaluation of Various Turbulence Models for Shock-wave Boundary Layer Interaction Flows

Evaluation of Various Turbulence Models for Shock-wave Boundary Layer Interaction Flows
Author: Francis Kofi Acquaye
Publisher:
Total Pages: 53
Release: 2016
Genre: Electronic dissertations
ISBN:

Despite the modeling capabilities of current computational fluid dynamics (CFD), there still exist problems and inconsistencies in simulating fluid flow in certain flow regimes. Most difficult are the high-speed transonic, supersonic and hypersonic wall-bounded turbulent flows with small or massive regions of separation. To address the problem of the lack of computational accuracy in turbulence modeling, NASA has established the Turbulence Modeling Resource (TMR) website and has issued the NASA 40% Challenge. The aim of this challenge is to identify and improve/develop turbulence and transition models as well as numerical techniques to achieve a 40% reduction in the predictive error in computation of benchmark test cases for turbulent flows. One of the phenomena of considerable interest in the 40% Challenge is the shock-wave boundary layer interaction (SWBLI) that occurs on aircraft surfaces at transonic and supersonic speeds and on space vehicles at hypersonic speeds. The correct modeling of shock-waves is complex enough, but the occurrence of SWBLI adds to the complexity by promoting flow separation, heat transfer, and pressure gradients on the surface. SWBLI may occur in both the external and internal flow path of air and space vehicles; therefore, it is important to accurately predict this phenomenon to improve the design of aircraft and space vehicles. The majority of CFD codes utilize the Reynolds Averaged Navier-Stokes (RANS) equations and employ various turbulence models. The most common among these turbulent models are the one-equation Spalart-Allmaras (SA) model and the two-equation Shear Stress Transport (SST) k-[omega] model. In recent years the CFD community has, in greater number, also started to adopt Large-Eddy Simulation (LES), Direct Numerical Simulation (DNS), and hybrid RANS-LES approaches for improving the accuracy of simulations. However currently, solving the RANS equations with eddy-viscosity turbulence models remains the most commonly used simulation technique in industrial applications. In this research, the one-equation Wray-Agarwal (WA), SA, and SST k-[omega] turbulence models are used to simulate supersonic flows in a 2D compression corner at angles of 8° and 16°, a partial axisymmetric flare of 20°, a full-body conical axisymmetric flare of 20°, and an impinging shock over a flat plate at 6°, 10°, and 14°. The ANSYS Fluent and OpenFOAM flow solvers are employed. Inflow boundary conditions and mesh sensitivity are examined to ensure the grid independence of computed solutions. For each of the three turbulence models, heat transfer, surface pressure, skin friction, and velocity profiles are compared with the available experimental data. It is found that the results from the WA model are in similar or better agreement with the experimental data compared to the SA and SST k-[omega] models for the majority of cases considered.

Shock Wave-Boundary-Layer Interactions

Shock Wave-Boundary-Layer Interactions
Author: Holger Babinsky
Publisher: Cambridge University Press
Total Pages: 481
Release: 2011-09-12
Genre: Technology & Engineering
ISBN: 1139498649

Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.

Turbulence Models and Their Application

Turbulence Models and Their Application
Author: Tuncer Cebeci
Publisher: Springer Science & Business Media
Total Pages: 140
Release: 2003-12-04
Genre: Science
ISBN: 9783540402886

After a brief review of the more popular turbulence models, the author presents and discusses accurate and efficient numerical methods for solving the boundary-layer equations with turbulence models based on algebraic formulas (mixing length, eddy viscosity) or partial-differential transport equations. A computer program employing the Cebeci-Smith model and the k-e model for obtaining the solution of two-dimensional incompressible turbulent flows without separation is discussed in detail and is presented in the accompanying CD.

Turbulence Model Assessment for High Speed Compressible Flows

Turbulence Model Assessment for High Speed Compressible Flows
Author: Vijaykumar Gopalakrishnan
Publisher:
Total Pages: 80
Release: 2005
Genre:
ISBN:

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.

Theoretical Investigation of Three-Dimensional Shock Wave Turbulent Boundary Layer Interactions

Theoretical Investigation of Three-Dimensional Shock Wave Turbulent Boundary Layer Interactions
Author: D. D. Knight
Publisher:
Total Pages: 52
Release: 1984
Genre:
ISBN:

The focus of the research effort is the understanding of three-dimensional shock wave-turbulent boundary layer interactions. The approach uses the full mean compressible Navier-Stokes equations with turbulence incorporated through the algebraic turbulent eddy viscosity model of Baldwin and Lomax. This year's principle accomplishments are (1) the Baldwin-Lomax model was evaluated for a series of non-separated two-dimensional turbulent boundary layers. (2) the 3-D Navier-Stokes codes was rewritten innto CYBER 200 FORTRAN. (3) the computed results for the 3-D sharp fin alpha sub g = 10 deg were compared with the results of a separate calculation by C. Horstmann using the k-epsilon turbulence model, and the experimental data of McClure and Dolling. and (4) the 3-D sharp fin at alpha sub g =20 deg was computed, and the results compared with the available experimental data. The examination of the flowfield structure of the 3-D sharp fin at alphaa sub g = 20 deg was initiated. Originator supplied keywords include: High speed flows; Viscous-inviscid interactions; Shock-boundary layer interactions; Computational fluid dynamics; Navier-Stokes equations; and Turbulence.