An assessment of several turbulence models for supersonic compression ramp flow

Forsythe, James R.; Hoflmannf, Klaus A.; Damevin, Henri-Marie

doi:10.2514/6.1998-2648

Cited by 14 publications

(12 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 The models cannot predict the size of the separation region, the peak heat transfer rate at reattachment, and the mean velocity profiles on the ramp. 4,5 Some attempts have been made to improve the predictions, e.g. realizability constraint, 4 compressibility correction, 5,6 length-scale modification 6 and rapid compression correction.…”

Section: Introductionmentioning

confidence: 99%

“…4,5 Some attempts have been made to improve the predictions, e.g. realizability constraint, 4 compressibility correction, 5,6 length-scale modification 6 and rapid compression correction. 6 The outcome of the modifications vary from model to model and also with the test conditions, which point to the possibility that some key physical processes are either modeled incorrectly or not included in the models.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling shock unsteadiness in shock/turbulence interaction

2003

View full text Add to dashboard Cite

The RANS (Reynolds averaged Navier-Stokes) equations can yield significant error when applied to practical flows involving shock waves. We use the interaction of homogeneous isotropic turbulence with a normal shock to suggest improvements in the k − model applied to shock/turbulence interaction. Mahesh et al. 1 and Lee et al. 2 present direct numerical simulation (DNS) and linear analysis of the flow of isotropic turbulence through a normal shock, where it is found that mean compression, shock unsteadiness, pressurevelocity correlation and upstream entropy fluctuations play an important role in the interaction. Current RANS models based on the eddy viscosity assumption yield very high amplification in the turbulent kinetic energy, k , across the shock. Suppressing the eddy viscosity in a shock improves the model predictions, but is inadequate to match theoretical results at high Mach numbers. We modify the k -equation to include a term due to shock unsteadiness, and model it using linear analysis. The dissipation rate equation is similarly altered based on linear analysis results. These modifications improve the model predictions considerably, and the new model is found to match the linear theory and DNS data well.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling shock unsteadiness in shock/turbulence interaction

2003

View full text Add to dashboard Cite

show abstract

“…Both the standard and shock-unsteadiness corrected k-ω models do not include any compressibility corrections,, as they are found to deteriorate model predictions in the undisturbed boundary layer upstream of the interaction. 26,27 Compressibility corrections of the form of dilatational dissipation reduce the turbulent kinetic energy in the boundary layer, and thus decrease the skin friction coefficient compared to well-established correlations for zero pressure-gradient turbulent boundary layers.…”

Section: Simulation Methodologymentioning

confidence: 97%

Variable turbulent Prandtl number model applied to hypersonic shock/boundary-layer interactions

Roy

Sinha

2018

2018 Fluid Dynamics Conference

View full text Add to dashboard Cite

Interaction of shock waves with turbulent boundary-layers can enhance the surface heat flux dramatically. Reynolds-averaged Navier-Stokes simulations based on constant turbulent Prandtl number often give grossly erroneous heat transfer predictions in SBLI flows. This is due to the fact that the underlying Morkovin's hypothesis breaks down in the presence of shock waves; thus, the turbulent Prandtl number can not be assumed to be a constant. In our recent work (Roy, Pathak and Sinha,AIAA 2017), we developed a new variable turbulent Prandtl number model based on linearized Rankine-Hugoniot conditions applied to shock-turbulence interaction. The turbulent Prandtl number is a function of the shock strength and we proposed a shock function to identify the location and strength of shock waves. The shock function also simulates the post-shock ralaxation of the turbulent heat flux, akin to that observed in canonical shock-turbulence interaction. In this work, we extend the variable turbulent Prandtl number model for hypersonic flows by considering the influence of upstream total temperature fluctuation on turbulent heat flux. The model is combined with the well-validated shock-unsteadiness k-ω model and is used to study eight test cases involving shock/boundary-layer interactions at Mach numbers ranging from 5 to 11. Comparison with experimental data shows significant improvement in the surface heat transfer rate in the interaction region. The shock function is also used to propose a robust form of the existing shock-unsteadiness k-ω model that simplifies the numerical implementation enormously. NomenclatureP r T Turbulent Prandtl number P k Production term of turbulent kinetic energy S ij Symmetric part of mean strain rate tensor S ii Mean dilatation b 1 Shock-unsteadiness damping parameter A uT Correlation between temperature and velocity fluctuations r Density ratio c f Skin friction co-efficient q w Wall heat flux, W/cm 2 δ 0 Boundary-layer thickness upstream of interaction, m k Turbulent kinetic energy, m 2 /s 2 ω Specific dissipation rate of turbulent kinetic energy, s -1 ξ t Instantaneous shock speed, m/s ψ Shock function Subscript ∞ Free-stream condition

show abstract

“…The standard k-ω model of Wilcox [7] and the shock unsteadiness modified k-ω model of Sinha et al [15] are used for turbulence closure. The turbulence models do not include any compressibility corrections, as they are found to deteriorate model predictions in the undisturbed boundary layer upstream of the interaction [23,24]. Compressibility corrections of the form of dilatational dissipation reduce the turbulent kinetic energy in the boundary layer, and thus decrease the skin friction coefficient compared to well-established correlations for zero pressure-gradient turbulent boundary layers.…”

Section: Methodsmentioning

confidence: 99%

Variable Turbulent Prandtl Number Model for Shock/Boundary-Layer Interaction

2018

View full text Add to dashboard Cite

Interaction of shock waves with turbulent boundary layers can enhance the surface heat flux dramatically. Reynolds-averaged Navier-Stokes simulations based on constant turbulent Prandtl number often give grossly erroneous heat transfer predictions in SBLI flows. This is due to the fact that the underlying Morkovin's hypothesis breaks down in the presence of shock waves; thus, the turbulent Prandtl number can not be assumed to be a constant. In this paper, we develop a new variable turbulent Prandtl number model based on linearized Rankine-Hugoniot conditions applied to shock-turbulence interaction. The turbulent Prandtl number is a function of the shock strength and we propose a shock function to identify the location and strength of shock waves. The shock function also simulates the post-shock relaxation of the turbulent heat flux, akin to that observed in canonical shock-turbulence interaction. The model is combined with the well-validated shock-unsteadiness k-ω model and is applied to the complex shock topology observed in oblique shock-turbulent boundary layer interactions. Comparison with experimental data shows significant improvement in the surface heat transfer rate in the interaction region, both for attached and separated SBLI cases. The shock function is also used to propose a robust form of the existing shock-unsteadiness k-ω model that simplifies the numerical implementation enormously.

show abstract

An assessment of several turbulence models for supersonic compression ramp flow

Cited by 14 publications

References 17 publications

Modeling shock unsteadiness in shock/turbulence interaction

Modeling shock unsteadiness in shock/turbulence interaction

Variable turbulent Prandtl number model applied to hypersonic shock/boundary-layer interactions

Variable Turbulent Prandtl Number Model for Shock/Boundary-Layer Interaction

Contact Info

Product

Resources

About