Analysis of Delta Wing Vortical Substructures Using Detached-eddy Simulation

An understanding of the vortical structures which comprise the vortical flowfield around slender bodies is essential for the development of highly maneuverable and high angle of attack flight. This is primarily due to the physical limits these phenomena impose on aircraft and missile s at extreme flight conditions. Demands for more maneuverable air vehicles have pushed the limits of current CFD 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 of this paper to demonstrate the ability of DetachedEddy Simulation, a hybrid RANS-LES method, to accurately model the vortical flowfield over a slender delta wing at Reynolds numbers above 1 million. Detached-Eddy Simulation 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 which roll up to form the leading-edge vortices. Very detailed experiments performed at ONERA using 3-D 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 vortical flowfield. INTRODUCTION