Aeroacoustic performance of a seal vibrissa shaped cylinder.

Bio-inspired geometries have many applications in engineering, including in the field of noise control. In this work, the aeroacoustic performance of a seal vibrissa shaped cylinder (SVSC) is investigated and compared to that of a circular cylinder at Re = 37 000. Experiments conducted in an anechoic wind tunnel are compared to results from a hybrid aeroacoustic simulation with excellent agreement observed between the two. The overall sound pressure level is found to be 24.3 dB lower for the SVSC, and no prominent narrowband component is observed in the acoustic spectrum. Analysis of the flow field and surface pressure fluctuations reveals that this is because the usual large-scale alternating vortex shedding realized for bluff body flows is absent for the SVSC. Instead, smaller uncorrelated vortices are shed from the upper and lower sides of the geometry, which, when combined with a lower spanwise correlation, results in a much lower acoustic intensity spread over a broader frequency range.