On the passive control of aeroacoustics noise behind a square cylinder

Abstract

This study investigated the application of a splitter plate as a passive control method for reducing the aerodynamic sound of square cylinders. To control the noise and vortex shedding, the splitter plates attached to the downstream of the square cylinder have been used. The flow is assumed to be unsteady and it is simulated using the URANS equations model k-ω-SST. Aerodynamic noise calculations are carried out by the use of F-fowcs Williams-Hawkins analogy. To verify numerical results, the sound pressure level (SPL) obtained in different situations (Microphone position) is compared with the experimental results, and a good agreement is observed. The simulation is carried out with different lengths of the splitter, and the results can be divided into three groups besides the baseline configuration as well. In the first group, when the length of the splitter varies from 0.2 to 2D, noise is noticeably reduced by about 23 dB. In the second group, the length of the splitter increases from 3 to 5D, and the SPL is increased by about 42 dB. In the third group, the length of the splitter varies from 6 to 8D, which in turn the noise is decreased by about 4 dB (Compared to the second group). Results show that adding the splitter reduces the mean drag force generally. But the changes in the lift fluctuations are similar to the SPL variations. The results reveal that the optimal splitter length through which noise, RMS lift, and drag coefficients are reduced, occurs for a Splitter in the first category (i.e., L = 0.2–2D).