Numerical Simulation of Flow around Rectangular Cylinders Using the Boltzmann Equation

A two-dimensional unsteady flow past a rectangular cylinder has been investigated numerically using the Boltzmann equation. The effect of cylinder aspect ratio varying from 1 to 10 and the flow Reynolds number from 10 to 400 on flow pattern has been analyzed. Results are presented in terms of drag, lift and pressure coefficients and Strouhal number of vortex shedding. Flow visualization images in the wake of the cylinder are shown and discussed. It was found that the shape and size of the recirculation bubble downstream of the cylinder are strong functions of its aspect ratio. Drag, lift, pressure coefficients and Strouhal number strongly depend on Re in steady regime while a dependence becomes weaker in unsteady flow regime. The flow configuration over a cylinder also varies with the aspect ratio. In addition, the present predictions are compared with numerical and experimental results from other works and a good agreement is reached.