MANIPULATION OF THE STARTING SEMICIRCULAR-CYLINDER NEAR-WAKE BY MEANS OF A SPLITTER PLATE

Abstract

As an example of flow controller, a short ID-long splitter plate is selected to manipulate the wake of an impulsively started flat-back semicircular cylinder (of diameter D) exhibiting fixed separation points. The way the plate-interaction develops with time and modifies the early vortex formation and shedding is analyzed with details by means of two complementary techniques of visualization (dispersed solid particles and dye filaments) when, positioned along the downstream center plane, the body-to-plate gap ranges from 0 to 1D and the Reynolds number is 600. Both topological observations like the possible occurrence and development of more or less important secondary separations and vortices, the shifting of the vortex shedding to the trailing edge of the plate and quantitative measurements characterizing the recirculating zone geometry and velocity magnitude are proposed and compared with the previous data by Boisaubert et al. [1] related to the plain body wake.