NUMERICAL STUDY OF AERODYNAMIC NOISE REDUCTION ON A SQUARE CYLINDER USING SPLITTER

In this article, a numerical study of the effect of splitter plates located on the wake zone of a square cylinder on vortex formation control and aerodynamic noise reduction is presented. The flow is assumed to be unsteady and is simulated using the URANS equations and applying the turbulence model $K-omega-SST$. Aerodynamic noise calculations are carried out by the use of lighthill analogy. For this purpose, a cylinder with a square cross-section (D = 10 mm) has been used and splitters are assumed to have a constant thickness of 2 mm with different lengths. In order to verify the numerical results, the sound pressure level obtained in different situations is compared with the experimental results, and good agreement is observed. The significant reduction of the level of sound pressure of 15% and the reduction of fluctuations with the increase of the Wake area, as well as the reduction of aerodynamic forces by applying splitter, are the results of this study. By applying a splitter with a length equal to the cylinder side, the difference in forward and backward pressure of the intermediate pressure decreases by about 40%, which results in a decrease of about 16% in the averaged drag. In this case, the Reynolds stress is reduced by about 60% as well as the pressure fluctuations by about 50%. The observation of the structure of the flow indicates that the splitter application is prevented from moving the fluid into the inner surface of the shear layers detached by the downstream splitter. The observation of the structure of the flow indicates that the splitter application is prevented from moving the fluid into the inner surface of the shear layers detached by the downstream spinner. Investigating the details of the unsteady flow structure shows that fluctuations in flow and aerodynamic forces have been reduced due to a longitudinal increase in the wake zone.