Numerical investigation on the flow around a square cylinder with an upstream splitter plate at low Reynolds numbers

Abstract

The present study focuses on the flow over a 2D square cylinder with a plate placed in front of it. An in-house code using the lattice Boltzmann method was employed for all the simulations presented. Few cases were simulated using the open source code Nektar++, the results obtained from both methodologies were compared. Regarding the plate, three related parameters, velocity ratio, distance between the plate and cylinder and the thickness of the plate, were studied in order to evaluate the impact of these parameters on the flow behavior. The interactions between these parameters were as well investigated. The effect of these parameters on flow transitional properties such as Hopf and Neimark–Sacker bifurcations were discussed. Whenever the velocity ratio exceeds a certain value, Kelvin–Helmholtz instabilities dominate the vortex shedding. As velocity ratio increases, drag coefficient and vortex shedding frequency increase. The POD method was employed to predict the flow behavior based on the existing information. It turned out the POD method is a trustable methodology to mathematically pre-investigate the flow field, therefore it is capable of saving large computational resources