Reproducing Vortex Topology Mode Alternation of a Generic Combat Aircraft Model by Means of Hybrid RANS-LES Simulations

Abstract

The unsteady flow phenomena of a delta wing configuration with multiple leading edges are investigated by means of high-resolution numerical simulation and comparisons with experimental data. The goal is to establish a validated numerical baseline for further research on potential mode alternations due to topological instabilities of the complex vortical flow, which have been observed on the DLR-F23 combat aircraft wind tunnel model during previous experiments. In order to draw conclusions from the underlying flow physics, it needs to be shown first, that coherent and plausible flow field data can be calculated by numerical simulations. Hence, a challenging test case at an angle of attack of α = 21◦ and a transonic Mach number of 0.85 is chosen. Comparisons between experimental and numerical data show, that the hybrid-RANS-LES approach reproduces the flow to a satisfying degree.