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为了有效地降低涡激噪声,研究了粘性流体通过涡激振动机翼的声辐射。采用Navier-Stokes方程描述二维机翼的流固耦合运动,用弹簧系统代替实际固体变形产生的回复力和力矩,翼型的运动是两个自由度,即垂直于来流的振荡和转动振荡;为了模拟涡激振动,机翼的初始攻角取得比较大,以便产生周期性的旋涡脱落及周期性的流体动力,后者与弹簧系统相耦合,引起振动,用Lighthill声比拟方法研究了由此引起的声辐射。计算结果表明:当涡脱频率和机翼的固有的振动频率一致时,发生锁定的现象,此时的声辐射达到最大。
In order to reduce the vortex-induced noise effectively, the acoustic radiation of the viscous fluid is excited by the vortex-induced vibration. The Navier-Stokes equations are used to describe the fluid-structure interaction of a two-dimensional wing. The spring system is used to replace the restoring force and moment produced by the actual solid deformation. The airfoil movement is two degrees of freedom, ie perpendicular to the incoming flow oscillation and rotational oscillation In order to simulate the vortex-induced vibration, the initial angle of attack of the wing is relatively large, in order to produce periodic vortex shedding and periodic hydrodynamic force, the latter coupled with the spring system, causing vibration, using Lighthill acoustic simulation method studied by This caused by acoustic radiation. The calculation results show that when the eddy frequency and wing natural vibration frequency coincide, the phenomenon of locking occurs, the sound radiation reaches the maximum at this time.