Visualization of low-Reynolds number flow above a finite-height square prism

A finite-height square prism immersed in a low Reynolds number uniform flow is visualized based on the mean velocity field generated by a large eddy simulation. The flow about the free-end of the prism, which connects directly into the wake, is analyzed in terms of the three-dimensional flow structure. A strong reverse flow exists along the surface of the free-end, which is supplied by the upward flow generated along the rear face of the prism by the primary vortex/recirculation zone in the wake. Two streamwise vortical structures are generated at the lateral corners of the leading edge of the prism. The structures grow in strength and their location moves toward the mid-plane of the prism flow field as they extend downstream. Cross-stream sections show that the reverse flow on the free-end also entrains fluid from the lateral sidewalls.