基于平面声源进行结构声辐射有源控制的实验研究

采用分布式平面声源作为次级声源,对振动钢板的声辐射进行了抵消实验,验证了以往研究中的一系列关键理论。实验研究结果表明:一个平面声源可以控制钢板奇-奇模态的声辐射,两个平面源可以控制结构偶-奇或奇-偶模态的声辐射,同时也可以控制结构奇-奇模态的声辐射;平面声源的面积和布放位置对降噪效果有重要影响,采用单个平面声源控制时,平面声源面积越大,控制效果越好;基于近场声压的误差传感策略是有效可行的,实际中,将近场测量面的声功率作为有源控制的目标函数与总声功率作为目标函数是一致的;控制后远场声压和声强都得到有效降低,部分区域的声能向声源流动,近场声压及声强分布也发生显著变化。

Experimental study on active control of sound radiation based on planar sound sources

Active control of sound radiation from a vibrating steel plate using distributed planar secondary sources is investigated experimentally.The results show that(1)On u- sing one planar secondary source,the sound power of the(odd,odd)modes can be re- duced;(2)On using two planar secondary sources,the sound power of not only the( odd, odd)modes but also the(odd,even)modes can be reduced;(3)The areas and the loca- tions of the planar secondary sources have important influence on noise reduction;On using one planar secondary source,the larger the area is,the better the control effect is.(4) The near field pressure based error sensing strategies are effective and feasible.The sound power calculated in terms of the sound pressures above the near field measuring plane can be used as an objective function which is consistent with the total radiated sound power. (5)After control,the far field pressure and intensity can be reduced and some partial acoustic energy is transferred into the near field,and that the distribution of the near field pressure and intensity are also changed distinctly.