Analysis of delta-wing vortical substructures using detached-eddy simulation

An understanding of the vortical structures that comprise the vortical flowfield around slender bodies is essential for the development of highly maneuverable and high-angle-of-attack flight. This is primarily because of the physical limits these phenomena impose on aircraft and missiles at extreme flight conditions. Demands for more maneuverable air vehicles have pushed the limits of current computational fluid dynamics methods in the high-Reynolds-number regime. Simulation methods must be able to accurately describe the unsteady, vortical flowfields associated with fighter aircraft at Reynolds numbers more representative of full-scale vehicles. It is the goal here to demonstrate the ability of detached-eddy simulation (DES), a hybrid Reynolds-averaged Navier-Stokes/large-eddy-simulation method, to accurately model the vortical flowfield over a slender delta wing at Reynolds numbers above one million. DES has successfully predicted the location of the vortex breakdown phenomenon, and the goal of the current effort is to analyze and assess the influence of vortical substructures in the separating shear layers that roll up to form the leading-edge vortices. Very detailed experiments performed at ONERA using three-dimensional laser-Doppler-velocimetry measurement will be used to compare simulations utilizing DES turbulence models. The computational results provide novel insight into the formation and impact of the vortical substructures in the separating shear layers on the entire vertical flowfield.