Three Dimensional CFD Analysis of Rectangular Cylinder with Aspect Ratio of 0.4

Abstract

A rectangular cylinder with an aspect ratio of B/D smaller than 0.6 requires three-dimensional unsteady computational fluid dynamics (CFD) simulation since a three-dimensional flow is generated in the span-wise direction in the wake of this cross section. And it is known from previous studies that CFD simulation of two-dimensional section causes a large difference in the results of existing wind tunnel experiments. In this study, large eddy simulation (LES) is conducted in case of the aspect ratio B/D equals 0.4 and we verified two points, the span-wise length and the mesh size in the span-wise direction. These were examined by comparing the aerodynamic coefficients obtained in this study with the results of existing wind tunnel experiments. As a result, it was found that the mesh size in span-wise direction should be smaller than D/10 and the span-wise length should be longer than 4D when performing a three-dimensional CFD analysis on a rectangular cylinder with an aspect ratio of B/D smaller than 0.6.