Detached-Eddy Simulations of Vortex Breakdown over a 70-Degree Delta Wing

Abstract

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 due to the physical limits this phenomenon imposes 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. One of the goals of this paper is to demonstrate the ability of detached-eddy simulation, a hybrid Reynolds-averaged Navier―Stokes large-eddy simulation method, to accurately predict the vortical flowfield over a slender delta wing at Reynolds numbers above 1 × 10 6 . Although detached-eddy simulation successfully predicted the location of the vortex breakdown phenomenon in previous work, the goal of the current effort is to further validate the method with additional experimental data from the Office National d'Etudes et Recherches Aerospatiales, such as surface pressures and turbulent kinetic energy in the vortex core. The effect of grid density and an adaptive mesh refinement technique is also assessed through comparisons with the experiment. Detailed wind-tunnel geometry, such as tunnel walls and the sting mount system, are simulated and found to make a measurable difference. Finally, modeling the laminar-to-turbulent transition is demonstrated to have a significant effect on the vortical flowfield.