Abstract
Aerodynamic sound has been numerically predicted by two methods. First is DNS which solve the compressible Navier-Stokes equations directly, and Second is analyzing Lighthill Tensor which is the right side of Lighthill's equation. Recently, analyzing Lighthill Tensor is expected heighten because of high cost of DNS. However, this method still has several problems especially about an end of computational domain. To solve computational domain problem, we use DNS in this study. The sound field radiated from the two-dimensional square cylinder in a uniform flow is changed by the number of vortices captured by computation. In order to clarify acoustical vortex, we investigate sound mechanism. In addition, we calculate Powell's and Lighthill's acoustic sound sources.
