Delayed-VLES Model for the Simulation of Turbulent Flows

Speziale’s VLES is one of the hybrid RANS/LES methods according to previous researches. VLES method used a unified modelled stress equation that was adjusted by resolution control function. Due to the nature of compromising grid space information, VLES can conveniently lead to a modelled stress dissipation beneath the boundary layer by computing from coarse grid to fine grid. The present study proposes a delayed-VLES (DVLES) method which can improve the modelled stress dissipation phenomenon. The advantage of the DVLES is that the RANS simulation can be preserved in near-wall region by using a damping function. This new methodology is assembled with Menter’s SST model. Applications are conducted for the turbulent flat plate and turbulent flow past a NACA0021 airfoil at 60o incidence. The corresponding results are compared with VLES and URANS. It is demonstrated that the DVLES is favorably robust with the grid refinement.