Perfectly Matched Layer boundary conditions using in dns of flow around cylinder

Numerical simulation of flow around cylinder is a classical problem in computational fluid dynamics and computational aeroacoustics. The non-reflection boundary condition is one of the key technologies during the simulation. Perfectly Matched Layer (PML) boundary conditions for Navier-Stokes equations are used in the direct numerical simulation of flow around cylinder at low Reynolds number. And the effect of the size of computational domains on solutions is numerically studied. Numerical results reveal that: (1) Relative reflection errors caused by PML boundary conditions are very small. (2) Smaller computational domains can be used for the flow and acoustic field around the cylinder if PML boundary conditions are applied. (3) Slightly increasing of the width of up and down boundaries of the computational domain can greatly reduce the width of the outflow boundary, and maintain high accuracy of solutions with less calculation time.