Numerical Simulation of Unsteady Separated Flow over a Delta Wing Using Cartesian Grids and DES/DDES

Detached-Eddy simulation (DES) and Delayed Detached-Eddy simulation (DDES) based on SA and SST turbulent models were developed by using Cartesian grids. Associating with flexible deformation dynamic grid method on Cartesian grids,unsteady Reynolds-averaged Navier-Stokes (URANS), DES and DDES methods involving moving boundaries wereestablished. URANS, DES and DDES were evaluated for simulating the high angle of attack separated flow over a delta wing of 65 degrees swept and with sharp leading edge, showing that DES and DDES forecast the site of vortex breakdown more accurate, which means these methods are fit for simulating the large separated flow and can be adapted to the engineering applications. The study also simulated the unsteady separated flow around the oscillating delta wing. The results show that the pitching of the wing delays the flow separation and makes the flow field appearing hysteresis. It is meaningful to the design of modernastronauticaland aeronautical vehicles.