基于声涡转化对穿孔板切向流效应的研究

建立了一种有关切向流对小孔声阻抗影响的小扰动势流模型,其要点是使用法向质点速度连续而非广为采用的质点位移连续边界条件来匹配小孔剪切层两侧的声场,并在小孔前缘施加 Kutta条件以反映切向流效应的机理——锐缘处的声涡转化;模型中还考虑了实际应用中经常遇到的小孔形状和穿孔板厚度两个重要因素.理论预测的声阻和声抗与实验结果吻合良好.

AN INVESTIGATION OF GRAZING FLOW EFFECT ON THE IMPEDANCE OF A PERFORATED PLATE BASED ON SOUND-VORTEX INTERACTION

A linearized potential flow model is developed to study the grazing flow effect on the acoustic impedance of a perforated plate. This model uses the normal particle velocity continuity boundary condition rather than the widely used displacement continuity condition to match the unsteady flowfields separated by the orifice shear layer. The Kutta condition at the leading edge of the orifice is used to consider the mechanism of grazing flow effect, i.e. the sound-vortex interaction mechanism. The influences of the finite plate thickness and the orifice shape are also taken into account. Good agreement is obtained between the theoretical prediction and the experimental data both for the acoustic resistance and reactance.