Article
Reduction of aerodynamic noise from square cylinders through porous coating (en)
* Presenting author
Abstract:
The noise generated by square cylinders in a cross flow is a classical problem in aeroacoustics, which has been the focus of various experimental and numerical research studies and can be found in a variety of applications. Compared to the common case of a circular cylinder, the noise generation of a square cylinder is more complex, as there is an additional dependency on the angle with respect to the incoming flow. Thus, in cross flow the vortex shedding and the subsequent generation of tonal noise are not just influenced by the Reynolds number, but also by the angle of incidence.In a set of detailed acoustic experiments performed in an aeroacoustics wind tunnel, the effect of a porous coating on the sound pressure level and Strouhal number of the generated far-field noise of a square cylinder has been investigated. The angle of incidence was varied from 0 to 90 in 5-degree intervals and the flow speed was varied from 13.5 to 47.5 m/s, resulting in Reynolds numbers ranging from 20000 to 65000. The results show that the porous coating leads to a notable reduction of the tonal noise peak and has strong influence on the frequency of the vortex shedding.