Vortex Wake of Laminar Flow around Two Side-by-Side Elliptic Cylinders

Abstract

This study clarifies the characteristics of the vortex wake of flow around two elliptic cylinders in the side-by-side arrangement at a Reynolds number of 100. The cylinders have their axis ratio of 0.5, and their spacing varies from 1.2D to 2.5D, where D is the projection of the cylinder onto the vertical axis. Four flow configurations, such as two normal, convergent, divergent, and same-angle-of-attack elliptic cylinders, are examined. The simulation results show that nine flow patterns can take place, such as steady vortex pair, a single bluff body flow, two anti-phase synchronized Karman vortex streets, two in-phase synchronized vortex streets, two anti-phase synchronized Karman vortex streets followed by steady shear layers, steady shear layers followed by vortices and then a recreation of steady shear layers, steady shear layers followed by a Karman vortex street, flip-flopping wake, and chaotic flow. These patterns significantly depend on the spacing and their configuration.