On the onset of vortex shedding from 2D confined rectangular cylinders having different aspect ratios: Application to promote mixing fluids

Comparison of: mass fraction contours, (a) and (b); streamlines, (c) and (d); and dimensionless vorticity contours, (e) and (f), for AR = 1/2, ReH = 200, Sc = 1E4 and the indicated blockage ratios.