Vortex-generating shock control bumps for robust drag reduction at transonic speeds

The 3D contour bump has been integrated with vane-type vortex generators to weaken the shock wave and suppress potential flow separation at higher transonic speeds. The integrated vortex-generating shock control bump is parameterized as a whole, in a manner that the contour bump is designed for shock control and the vortex-generating fins are integrated to the contour bump for separation control. This allows the balance between the two factors affecting the total wing drag. The optimization studies based on the Reynolds-averaged Navier–Stokes equations have been carried out to find the optimal vortex-generating bump designs at the given design conditions. Single-point and multipoint global optimizations are carried out to search the optimum parameters at the corresponding design points. It is found that the vortex-generating bump can further reduce the total drag at the higher transonic Mach numbers due to the alleviation of after-bump streamwise separation by a pair of counter-rotating vortices generated. The inclusion of the vortex generators in the bump design allows for a better balance of the design in controlling both the shock strength and the flow separation after the bump at higher Mach numbers. A multipoint optimization leads to a robust vortex-generating bump design for a range of Mach numbers. The distinctive vortical flow structures induced by the vortex-generating bump are highlighted and discussed.