Numerical investigations on the flow over cuboids with different aspect ratios and the emitted noise

Abstract

The effect of aspect ratio on the flow over cuboids in cross-flow is investigated numerically, together with the noise emitted to the far field. The near-field flow features are obtained using the delayed detached eddy simulation approach and the far-field noise is predicted using the Ffowcs Williams-Hawkings acoustic analogy. Ten values of aspect ratio are studied in the current work ranging from 1/6 to 12 at three Reynolds numbers between 50 000 and 200 000. Aerodynamic coefficients, flow patterns, and pressure distributions along the cuboid surfaces are studied in detail with respect to cuboid aspect ratio for different Reynolds numbers. It is found that the separated flow from the leading edge reattaches to the lateral surfaces of cuboids with aspect ratios smaller than unity, while a secondary vortex is formed near the trailing edge for larger aspect ratios. In addition, the aspect ratio has considerable effect on the tonal peak in the far-field noise spectra from the cuboids occurring for aspect ratios greater than 1.