Unsteady analyses of the flow separation on the rear window of a simplified ground vehicle model.

Abstract

This paper presents the results of an experimental investigation of the separated flow over the 25 deg. inclined rear slanted surface of an Ahmed body. Experiments performed using hot wire anemometry and PIV concentrate on the symmetry plane of the geometry. Results show an average separated flow as well as a low Strouhal number spectral activity. POD analysis applied on the PIV instantaneous velocity fields show that the lower order mode correspond to a “flapping” behavior of the separation on the rear inclined surface, oscillating between a fully separated and a quasi-fully attached configurations.