Laminar flow across an unbounded square cylinder with suction or injection.

The flow around a horizontal square cylinder with uniform suction or injection at the front and rear sides is considered in the present paper. The problem is investigated numerically with a finite volume method using the SIMPLE algorithm. This flow has been investigated in the past for Reynolds numbers greater than 70. In the present work, the investigation is extended to very low Reynolds numbers (up to 0.001, Stokes flow) including eight different cases concerning suction-injection at the two sides. It is found that the drag coefficient takes negative and zero values in many cases and varies linearly at low Re numbers. In all eight cases, the vortices around the cylinder have been calculated. It is found that at low Re numbers, some vortices are symmetrical both about the horizontal and vertical cylinder axes. [ABSTRACT FROM AUTHOR]