Effect of dual splitter plate attached with a square cylinder immersed in a uniform flow

Abstract

In this paper we made a numerical study on control of vortex shedding and drag reduction of a cylinder by attaching splitter plates. The wake structure of the cylinder of square cross-section with attached splitter plate is analyzed for Reynolds number, based on the incident stream and height of the cylinder, up to 150. The length of the splitter plate, L is taken between the range 0 ≤ L ≤ 6. The Navier-Stokes equations governing the flow is solved by the finite volume method over staggered grid arrangement. We have used the SIMPLE (Semi-Implicit Method for Pressure- Linked Equation) algorithm for computation. Our results show that the presence of a splitter plate upstream of the cylinder reduces the drag but it has a small impact on the vortex shedding frequency. It is found that an upstream splitter plate leads to a significant reduction is drag force when the length of the plate L is 0 ≤ L ≤ 3. However, for 3.5 ≤ L ≤ 4.75 the reduction in drag force is low and when L ≥ 5, there is no effect of the splitter plate on the drag experienced by the cylinder. The presence of a downstream splitter plate damps the vortex shedding frequency. The entrainment of fluid into the inner side of the separated shear layers is obstructed by the downstream splitter plate. Our results suggest that by attaching splitter plates both upstream and downstream of the cylinder vortex shedding can be suppressed as well as a reduction in drag can be obtained.We made a parametric study to determine optimal length of the splitter plates attached upstream and downstream of the cylinder so as to achieve low drag and low vortex shedding frequency.