Delayed detached eddy simulations of fighter aircraft at high angle of attack

The massively separated flows over a realistic aircraft configuration at 40\(^{\circ }\), 50\(^{\circ }\), and 60\(^{\circ }\) angles of attack are studied using the delayed detached eddy simulation (DDES). The calculations are carried out at experimental conditions corresponding to a mean aerodynamic chord-based Reynolds number of \(8.93\times 10^{5}\) and Mach number of 0.088. The influence of the grid size is investigated using two grids, \(20.0\times 10^{6}\) cells and \(31.0\times 10^{6}\) cells. At the selected conditions, the lift, drag, and pitching moment from DDES predictions agree with the experimental data better than that from the Reynolds-averaged Navier–Stokes. The effect of angle of attack on the flow structure over the general aircraft is also studied, and it is found that the dominated frequency associated with the vortex shedding process decreases with increasing angle of attack.