穿孔板在切向流条件下非线性效应的理论与实验研究

流过声衬表面的切向流和高声压级的声场对于穿孔板共振结构的声学特性有这非常显著的影响。本文从波涡相互作用机制出发,发展了一种旨在研究矩形穿孔板在切向流条件下非线性效应的离散涡模型。同时用双传声器法测量了不同几何参数的穿孔板的声阻抗随偏流速度及声压级的变化情况。将本文的实验与理论结果进行了对比分析,对比的结果表明本文的实验与理论结果符合良好。

AN INVESTIGATION OF NON-LINEAR PROPERTIES OF PERFORATED PLATE WITH THE EFFECT OF GRAZING FLOW

A perforated liner is widely used in the suppression of noise, elimination of combustion instability of reduction of acoustic fatigue. In the present paper, a discrete-vortex model is employed to study nonlinear acoustic properties of an orifice. Compared with the previous models, the present model has the advantage of considering the effect of grazing flow with high sound pressure level and taking the detailed vortex motion around an orifice into account. For a consinoidal sound pressure, the time-history of the average velocity though the orifice is computed, and the nonlinear distortion of the velocity is examined by means of the Fourier decomposition. In addition, some experimental investigations are carried on to investigate the nonlinear acoustic properties of an orifice. The comparison between the theoretical and experimental results is also presented in this paper.