Numerical simulation of cross-flow around four circular cylinders in-line square configuration near a plane wall at supercritical Reynolds number

Abstract

In this research, it would be investigated numerically the effects of spacing between centres of cylinders (L) on flow characteristics around four circular cylinders in in-line square configuration near a plane wall at supercritical Reynolds number. A spacing ratio between centres of cylinders (L/D) would be varied. It is set at L/D = 2.0, 2.7, and 4.0, while a gap ratio between the surface of lower cylinders and the wall (G/D) was fixed at 0.2. To analyse flow characteristics around cylinders is used FLUENT 6.3.26 software. Two-dimensional Unsteady Reynolds Averaged Navier Stokes equations and SST k-ω turbulence equations are solved with finite volume method. This simulation was performed at Reynolds number 8.4 × 106 based on a single circular cylinder diameter and free stream velocity. The numerical results show that at supercritical Reynolds number separation point of the upstream cylinders and the downstream cylinders move far from front-ward of cylinder, while a minimum pressure of cylinder-1 decrease particularly at lower surface. At the downstream cylinders, increasing of spacing ratio cause of reattachment point at lower surface move to front-ward. While at the plane wall, increasing of spacing ratio cause of the negative pressure points starts to recover the static pressure move to back-ward of wall.