Mitigation of aerodynamic sound for a laminar flow past a square cylinder using a pair of cowl plates

A new arrangement of splitter plates has been proposed for the mitigation of aeroacoustic noise generated by the two-dimensional laminar flow over a square cylinder at the Reynolds number Re = 100 and the Mach number M = 0.2. The proposed arrangement involves a pair of cowl plates (arc-shaped splitter plates) symmetrically positioned on either side of the wake center-line near the rear corners of the square cylinder. Direct numerical simulations have been carried out to analyze the nature of flow and flow induced sound fields. Unsteady, two-dimensional, compressible fluid flow equations are solved using high-resolution, space–time accurate, dispersion relation preserving schemes. Simulations have been performed for various radial locations of the cowl plates. It is observed that the maximum reduction in sound pressure level of around 24 dB is possible using the proposed cylinder and cowl plate arrangement. Based on the observed directivity patterns, we have classified the sound fields into three different regions.