微缝共振器的非线性吸声机理

Nonlinear acoustic dissipation mechanism of a slit resonator

为模拟高声压级时微缝处涡声相互作用现象并计算微缝声阻抗,发展了一种离散涡模型.联合微缝离散涡模型和一维声传播模型,计算了微缝共振器的声阻抗和吸声系数.数值结果表明,微缝声学性质主要取决于涡脱落和脱落涡层的演化;共振器的吸声系数随着入射声压级的增加而增大;入射声波频率对共振器吸声系数有显著影响.研究结果和先前直接数值模拟的结果符合较好.

To simulate the vortex/sound interaction phenomenon at a slit with high sound pressure level and calculate the acoustic impedance of the slit,a discrete vortex model was set up.By combining the discrete vortex model with a one-dimensional sound propagation model,the acoustic impedance and the absorption coefficient of the slit resonator were calculated.The numerical results reveal that the acoustic properties of the slit are dominated by the vortex shedding and the evolution of the vortex sheet;the absorption coefficient of the resonator increases with the increase of the sound pressure level;the frequency of the incident sound has significant influence on the absorption coefficient of the resonator.The present results agree well with the previous direct numerical simulation（DNS） results.