开口回流式汽车风洞结构的声固有特性分析

Analysis of sound natural property for open-jet closed circuit automotive wind tunnel

将开口回流式风洞整体作为研究对象,建立变截面管道回路的声学分析模型,利用管道中的声传播理论,得到确定风洞流道内声空间声固有特性的方法;进而对同类型的某模型风洞的声固有特性进行计算,并与该模型风洞的测量结果和现有的研究方法得出的结果比较,说明本文的研究方法能较全面准确地确定无流或低风速风洞中的声固有特性,从而也较清楚地解释了引起这类风洞低频颤振现象的声响应特性,是对低频颤振机理的进一步探索。

Considering the whole open-jet closed circuit automotive wind tunnel, an acoustic model for variable section tube-circuit is set up, and the way to calculate the sound natural property of wind tunnel is obtained by using the sound propagation theory along tubs. The sound natural property of a certain wind tunnel model of such ldnd of wind tunnels is calculated. And the comparisons among the testing results, the results got from the existing method and the results calcuated by the way in this paper are made. It is shown that the way in this paper can completely and exactly confirm the sound natural property of the wind tunnel without flow or with low wind speed, and can rather elearly explain the sound response causing low frequency pulsation, which is a further probe into the mechanism of low frequency pulsation.