Towing tank PIV measurements on 2- and 4-vortex systems IGE

Abstract

The present report is part of the WP 3 “Wake evolution near the ground” of the FarWake project. Experimental investigations were performed in the tow tank at Göttingen to describe spatial-temporal flow evolution of 2- and 4-vortex systems in ground effect (IGE). The F13 model consisting of one or two rectangular wings is used as vortex generator and is towed along a ground plate at specific heights h/b = 0.5, 0.25, 0.125. In case of the 4-vortex system a span width ratio of b2/b1 = 0.3 and circulation ratios of Γ2/Γ1 = ± 0.3 are considered; i.e. co- and counter-rotating vortex pairs. A Stereo Particle Image Velocimetry setup is employed to determine the flow velocity fields in a cross plane. The flow fields are analysed with respect to flow separation at the ground, the generation of secondary vortices, the spatial-temporal development of the vortex trajectories and vortex circulation