摘要
有源吸声结构是近年来提出的吸收低频反射声的有效方案,对其物理机制的分析将为系统优化设计、次级源和误差传感器布放及控制目标选取等关键问题提供理论支持。在最小反射声功率条件下,从控制前后初、次级结构的反射声功率和净声强的变化,以及反射声场中声强的分布来阐述吸声降噪中的物理机制。结果表明,吸声降噪中的能量转换分为能量抑制、能量吸收以及能量抵消3种机制。从近场声强的角度看,有源吸声主要是通过声强幅度抑制和声强方向调整两种机制体现,控制前大部分区域反射声波的法向声强为负值,控制后则变为正值,即声能量在控制前向远场传递,控制后则流向吸声结构。
Active sound absorption structure proposed in recent years has been viewed as an feasible approach to effectively absorb low-frequency reflected sound. Analyzing the physical mechanism of noise reduction can offer theoretical help for some key issues,such as design optimization,the arrangements of secondary sources and error sensors,and selection of the control objectives.Under the minimization of the reflected sound power output,the physical mechanism of noise reduction is investigated by analyzing the changes of reflected sound power and net sound intensity of primary and secondary structures and the distribution of near field sound intensity before and after control.The results show that there are three mechanisms in noise reduction by active sound absorption structure,which are energy restraint,energy absorption and energy offset.In terms of near field sound intensity distribution,the effect of active sound absorption can be revealed by amplitude restraint and direction adjusting of the sound intensity. The normal sound intensity of the reflected sound wave is negative before control and turns to be positive after control in most regions,that is,the acoustic energy which is transferred into far field before control will flow to absorption structure after control.
出处
《振动工程学报》
EI
CSCD
北大核心
2010年第3期339-347,共9页
Journal of Vibration Engineering
基金
陕西省自然科学研究计划资助项目(2005E229)
关键词
有源吸声结构
反射声功率
几何反射
振动模态
声能量
active sound absorption structure
reflected sound power
reflection geometry
vibration mode
acoustic energy
