Steady and Unsteady Laminar Flow Past an Equilateral Triangular Cylinder for Two Different Orientations

Unconfined fluid flow past an equilateral triangle was numerically studied for laminar incompressible flow. Two configurations of the cylinder were studied. In the first configuration; a vertex was placed upstream and a side was placed in the downstream position normal to the flow, while in the second configuration; the orientation of the triangle was reversed, i.e. the side normal to the flow was placed upstream and a vertex was placed at the downstream. Both steady and unsteady simulations were performed at 30 ≤ Re ≤ 150. The results clearly show that the orientation of the triangle with the vertex at the downstream side stabilized the flow and delayed the onset of vortex shedding. Significant differences of drag coefficient, wake length, and velocity distributions were found between the two orientations of the equilateral triangle.