Numerical Investigation of Rotating Cylinders in Equilateral Triangular Configuration

Abstract

To study the changes in hydrodynamics of cylinders in equilateral triangular arrangement by the combined effects of rotation of the two downstream cylinders and gap spacing of the three cylinders, numerical simulations are done at rotational speeds range (0 ≤ α ≤ 5) where α is the non-dimensional rotation formulated as ωD/U, for three different gap spacing (L/D) where L being the center to center distance between the two cylinders and D being the diameter of the cylinder, of 1.1, 1.5 and 3.0 at Reynolds number of 100, that depicts typical two-dimensional vortex shedding. Effects of direction of rotation (same and inwards), is also studied. The upstream cylinder is kept stationary whereas upper and lower downstream cylinders rotate anti-clockwise (α > 0) and clockwise (α < 0) respectively, for inwards rotation while rotation is anti-clockwise (α > 0) for both the cylinders for same rotation, with the same magnitude of rotational speed for both cylinders. The main emphasis of this study is to find the critical rotational speed where vortex shedding is suppressed completely. The vortex dynamics involved is highly affected by the rotation and the gap spacing leading to various distinct flow structures.