粘性流体通过二维振荡圆柱的声辐射研究

Research on the Sound Radiation by Viscous Flow past the Vibrating Cylinder

本文建立了一个低马赫数下的求解远场声密度的数值模型 ,该模型利用Navier-Stokes方程计算二维粘性流体通过固定/弹性支撑圆柱的流场 ,利用Lighthill声比拟理论计算该流场产生的水动力噪声。文中仔细地给出了远场二维声辐射的公式。利用这些公式分别讨论了不同雷诺数下(Re<200和Re>5000)

A numerical model of far-field sound pressure at low Mach number was established based on the unsteady incompressible Navier-Stockes equations and Lighthill acoustic analogy. As for computation of sound field, the sound radiated from fixed cylinder and elastically supported cylinder separately was considered. The contributions of the volume quadrupole, surface dipole and equivalent monopole terms to the sound radiation were analyzed. Furthermore, the relation between vibrating cylinder and sound generation was studied. The investigation shows that the displacement is locked when the vibrating frequency of the cylinder is same as the frequency of the vortex shedding behind the cylinder, i. e. it is in resonance. The terms induced by the velocity of cylinder and the acceleration of cylinder are the largest, whereas they only show regular rhythm at other high Reynolds numbers. There are distinctly different contributions to sound generation under the two situations. This new discovery is of great significance for the vortex induced noise control and development of the acoustic stealth theory.