Simulation of a delta wing with two jets in ground effect

Abstract

Numerical simulations of the flow about a 60° delta planform wing, equipped with two thrust reverser jets, in ground effect are presented. These simulations are based on the solution of the three-dimensional thin-layer Navier-Stokes equations on a body-conforming, overset, multiple grid topology. An implicit, two-factor, numerical scheme with flux-splitting in the streamwise direction is used. The first set of simulations involves the validation of the numerical scheme by studying the impact of numerical parameters (e.g. grid refinement and dissipation levels) on the solution. The second set of simulations is performed to understand the effect of flow-field parameters (such as the height of the delta wing above the ground plane, the jet size, and the jet exit temperature) on the solution. Flow features such as jet deformation and ground vortex formation observed in experimental flow visualizations are captured. Comparisons with experimental data confirm the ability to simulate the loss of wing-borne lift, commonly referred to as “suck-down,” as the delta planform flies at slow speeds in close proximity to the ground. Detailed analysis of the numerical results has given insight into the structure of the ground vortex and the mechanisms of lift loss.