Effect of a splitter plate on flow over a semi-circular cylinder

In this study, two-dimensional unsteady laminar flow over a semi-circular cylinder (SCC) near a splitter plate was investigated numerically. Adding a splitter plate along the wake centreline downstream of the bluff bodies is an efficient passive means of controlling fully developed vortex shedding. Numerical simulations were done for different Reynolds numbers ranging from 100 to 500 in three different gaps (g: g = 0.0D to 4.5D) and two different splitter lengths (L-SP = 1 and 2D). Results indicate that by increasing the gap ratio, vortex shedding formed in the wake is suppressed and the oscillating amplitude of the lift coefficient decreases. On the other hand, drag, lift, and pressure coefficients representing the flow characteristics also vary as a function of the gap ratio at different Reynolds numbers. Extensive results on streamline patterns, wake characteristics (recirculation length), drag, lift, and pressure coefficients are presented to elucidate the interplay between the gap ratio and the Reynolds number and their influence on drag. Using the splitter plate at the downstream of the SCC causes the stretching of the vortex core and moves the centre of the vortex cores towards the leading edge of the plate. This phenomenon is caused by the reduction of the lift and drag coefficients.