Numerical simulation of sound generation by flow past a cylinder

The aeroacoustic sound generation by flow past a two-dimensional circular cylinder is investigated numerically. The compressible Navier- Stokes equations are solved by a proposed finite volume method. The numerical method is based on a third-order upwind finite-volume scheme in spatial derivatives. The Roe’s approximation Riemann solver is used for the numerical flux and an explicit second-order three-step Runge-Kutta scheme is used for the time marching. The flow variables, such as density, momentum, and pressure, around the near and middle field are obtained by the proposed numerical solver. Then the pressure field and the associated sound waves are computed by the Kirchhoff’s method. In this paper, a series flow parameters are considered, such as Mach number from 0.2 to 0.6 and Reynolds number from 900 to 90,000. A polar grid system is used in the calculations. The grid and time resolution studies are performed to see convergence of the computational solutions. To accurately apply the Kirchhoff’s method, the integral surface used in the method should include the nonlinear region. In this study, several integral surfaces for the Kirchhoff’s method are tested to check accuracy and convergence. The numerical results indicate that the decay rate of the strength of the pressure fluctuation is proportional to l/R, where R is the radius from the center of the circular cylinder.