High-Fidelity Simulations for Maneuvering Unmanned Combat Air Vehicle Configurations

In this paper a high-order computational method for the highly unsteady, complex vortical flows over unmanned combat air vehicle (UCAV) like configurations is presented. A sixth-order compact difference scheme with an eighth-order low pass filter is used to solve the Navier-Stokes equations. An implicit large-eddy simulation (ILES) method which exploits the high-order accuracy of the compact difference scheme and uses the discriminating higher-order filter to regularize the flow is used to model the transition and turbulence in these highly separated flows. This computational approach is applied to the detailed characterization of the flowfield over a low sweep delta wing at moderate Reynolds numbers and both low and moderate freestream Mach numbers. Computations exploring the control of the vortical flows above a swept delta wing by use of a dialectric-barrier-discharge (DBD) actuator are also presented. With the actuator located near the apex, significant movement of the vortex breakdown location and a dramatic transformation of the shear-layer substructures are demonstrated