Experimental investigation of cross-flow vortex structures in the wake region of a sphere using time-resolved PIV and POD analysis

摘要

We have presented an experimental investigation of un-steady flow over a sphere. Spatiotemporally resolved velocity measurements were taken at several cross-flow planes in the wake region of the sphere using TR-PIV technique. The flow statistics were calculated and presented here for the Reynolds number of 1,250 and at the planes z = 1D and_ z = 2D. The computed in-plane mean velocity vectors at z = 1D have shown the inner and outer flow regions, where the fluid par-ticles moved outward and inward, respectively. At the plane z = 2D, velocity vectors displayed swirling flow patterns and the in-plane mean velocity magnitude was found to be greater than that computed at plane z - 1D.