Laminar flow past a hemisphere

Numerical simulations are conducted for laminar flow past a hemisphere up to Re=300 in order to investigate its characteristics. It is found that unlike steady flows significant differences exist between unsteady flows past a hemisphere and a sphere. First, in the case of time-periodic planar-symmetric flow, alternating vortex shedding takes place behind a hemisphere with zero mean lift force, while nonzero mean lift force occurs for flow over a sphere. Second, there exists a time-periodic asymmetric flow regime for flow past a hemisphere, but it does not exist for flow past a sphere. It is also found that for flow past a hemisphere, the onsets of axisymmetry breaking and unsteadiness take place at lower Reynolds numbers than those for flow past a sphere.