高声强下微圆孔声学非线性效应vena收缩系数的研究

THE VENA CONTRACTA COEFFICIENT OF AN ORIFICE FLOW EXCITED BY HIGH-INTENSITY SOUND WAVE

在研究高声强下微圆孔声学非线性效应时,准定常模型的一个明显不足是采用固定不变的 vena收缩系数,因而影响了预测精度。本文联合一种准定常方法和离散涡方法,给出了 vena收缩系数随入射声强的变化曲线,并与实验结果符合得较好。将本文准定常方法与 vena收缩系数曲线相结合来预测非线性声阻,不仅预测精度高,而且十分简便,适用于高声强条件下穿孔板共振吸声结构的工程设计。

Constant value of vena contracta coefficient has been commonly used in the quasi-steady models for computing the nonlinear acoustic impedance of an oriflce. However, this assumption de- grades the accuracy of the theoretical models. In this paper, the relation between the vena contracta coefficient and the sound iniensity is quantitatively established by combining a discrete vortex method and a quasi-steady model for the nonlinear acoustic phenomenon, which shows good agreemeot with the previous experiment. It is demonstrated that, by the use of the proposed vena contracta coefficient- sound intensity curve, the quasi-steady model can accurately and efficiently predict the nonlinear acoustic impedance, thus being well suitable for engineering applications.