The Effect of Bionic V-ring Surface on the Aerodynamic Noise of a Circular Cylinder

Inspired by stripe shaped structure of owl wing feathers, V-ring surface was proposed in this paper to reduce the aerodynamic noise of a circular cylinder. The effects of V-ring surface on the aerodynamic and aeroacoustic performance of the cylinder were investigated by wind tunnel and numerical simulation. We tested the fluctuating pressure of the smooth cylinder and the V-ring surface cylinder by pulsating pressure sensor in FD-09 wind tunnel of China Academy of Aerospace Aerodynamics (CAAA). At a wind speed of 42m1s, the Reynolds number is 1.62x10(5) based on the cylinder diameter D of 58mm. The test results showed that the overall fluctuating pressure on the measurement points of the V-ring surface cylinder was significantly decreased compared with the smooth cylinder. The mechanisms of aerodynamic noise control of circular cylinder by V-ring surface were studied by the Large Eddy Simulation (LES) and the Ffowcs Williams and Hawkings (FW-H) equation. The numerical simulation results showed that the aerodynamic noise of the V-ring surface cylinder was reduced by 4.1dB compared to the smooth cylinder. The sound pressure of V-ring surface cylinder model is reduced when the lift fluctuation becomes lower. The V-ring surface is capable of reducing the frequency of the vortex shedding and controlling the fluctuating lift force induced by unstable vortices acting on the cylinder surface.