Vortex breakdown above a delta wing with sharp leading edge

Application Area 1: External Aerodynamics

Application Challenge AC1-09

Abstract

This test case is concerned with the prediction of vortex breakdown above a delta wing with a sharp leading edge at high angle of attack. In particular, the NASA delta wing geometry of Chu and Luckring (1996) is considered, which is also used in the Second International Vortex Flow Experiment (VFE-2). Within VFE-2, detailed experimental results at vortex-breakdown conditions have been obtained by Furman and Breitsamter (2009). Computations for this test case have been performed in the EU-project ATAAC, in particular consisting of Detached Eddy Simulations (DES).

The lift force on a delta wing is mainly determined by the suction due to the vortices above the wing. As the angle of attack increases, the vortices become stronger and the lift increases, until the vortices break down, the suction effect is lost, and the lift drops strongly. Hence, the computation of vortex breakdown is relevant for the prediction of the performance of aircraft employing delta-type wings.