具有流动和侧向Helmholtz共振器的驻波管内声场研究Ⅱ.实验验证及结果讨论
A study of sound field in a standing wave tube with flow and lateral Helmholtz resonator II. Experimental confirmation and results discussion
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摘要: 利用建立的具有流动和侧向Helmholtz共振器的驻波管的实验装置,成功地证实了作者所作的理论分析,包括有流动驻波管和Helmholtz共振器连接处的间断条件、驻波管末端的反射条件、切向流时Helmholtz共振器声阻抗,并实验确定了末端修正系数和等效半径系数。接着,应用理论分析和实验得到的结果讨论了流动对Helmholtz共振器性能和驻波管声场的影响,结果表明,流动会降低一些消声效果,但在具有流动的驻波管中采用Helmholtz共振器仍然是一种降噪的有效方法。Abstract: An experimental apparatus of a standing wave tube with flow and lateral Helmholtz resonator has been set up to verify the theoretical analysis presented by authors successfully, in which the discontinuity condition at the joint between the standing wave tube and Helmholtz resonator in the case of flow, the refection condition at the end of the standing wave tube and the acoustic impedance of Helmholtz resonator are included. Meanwhile the coefficients of end correct and equivalence radius have been obtained by experiments. Then several results from the theoretical analysis and experiments are used to discuss the effects of flow on the performance of Helmholtz resonator and the sound field in the standing wave tube. It is shown that using of Helmholtz resonator for the standing wave tube with flow is still a efficient method of noise reduction, even though because of flow the effect of noise reduction could be a little reduced.