Experimental and Numerical Analysis of a Streamwise Vortex Downstream of a Delta Wing

Kurzfassung

The present paper analyzes the vortical flow downstream of a delta wing. The Delta wing is designed to generate a vortex which resembles the vortex of a nacelle strake. The experimental results of stereo-PIV measurements performed at different positions downstream of the delta wing display the streamwise development of the vortex. The distributions of the mean axial and tangential velocity components and Reynolds-stresses characterize the vortex development. In addition, results of numerical simulations with the DLR TAU-code applying the Menter-SST eddy viscosity model and the SSG/LRR-Omega Reynolds-Stress model show the ability of the turbulence models to capture the vortex development. The experimental results indicate a preservation of the vortex strength and structure downstream of the delta wing. The Menter-SST model does not predict this preservation, rather it computes a rapid decay of the vortex strength and an increase of the vortex size. In contrast, the results of the SSG/LRR-Omega model are in good Agreement with the experiments concerning the mean flow development. However, turbulence in the vortex core is underpredicted by both turbulence models.