Influence of Turbulence Model on Numerical Simulation of Transonic Buffet over a Delta Wing

Abstract

At the high angle of attack of delta wing in transonic speed, interaction between vortex and shock wave causes a vortex breakdown and the fluctuation of shock called ``buffet.'' We simulated this phenomenon using RANS approximation based on computational fluid dynamics approach. We examined the difference in vortical flow between three popular RANS models, SA, SA-R and SST. As a result, we obtained accurate results below the critical angle of attack of the occurrence of the buffet for any of turbulent models. However, we obtained a different simulation results in above the critical angle for each turbulence model. In particular, the prediction of the critical angle of vortex breakdown was different for each turbulence model. The results by the SST model were in good agreement with the experimental results, compared with the results by other models. After we examine this result in detail, we shows that SA and SA-R can not properly analyze the vortex structure.