Development of hybrid RANS/LES code and its validation

A computational code based on the hybrid RANS-LES approach is developed. The hybrid approach combines the delayed detached-eddy simulation(DDES) with an improved RANS-LES hybrid model aiming at wall modeling in LES(WMLES). In the code, the convective flux is solved using the fourth-order skew-symmetric scheme so as to diminish the negative effect of numerical dissipation. The Spalart-Allmaras(S-A) model is applied as a subgrid scale(SGS) model. To validate the developed code, homogeneous isotropic turbulence and turbulent channel flow are simulated and the results are compared with experimental data and DNS results. The results of the isotropic turbulence show that the fourth-order skew-symmetric scheme is adequate enough and the model works well coupling with the convective scheme. The results of the turbulent channel flow agree well with the DNS data, the predicted velocity profiles at Reynolds number from 178 to 2700 match well with the Reichardt's law, and the organized vortical structures are well captured.