Perforated Bluff-Body Wake Simulations: Influence of Aspect Ratio

Parallel computations of flow past a perforated plate of porosity 25% at Reynolds number 250 (based on plate width, d and inflow velocity, Uo) is carried out. The effect of aspect ratio is studied with different span-wise lengths of the domain (1d, 3d and 6d). Present results revealed that an aspect ratio of 6d is required to capture the transient wake dynamics. It was found that statistical quantities stemming from aspect ratio 3d and 6d cases agree with each other, though the dynamical behavior of the wake is very different. The signature period doubling effects associated with short constrained domains were visible in the 1d and 3d aspect ratio cases. Enforcing periodic boundary condition along the short span-wise domains may thus adversely affect the flow.