为实现强声的气动发声,设计了一种基于喷注型和谐振型组合的复合式气动声源,仅对喷注型声源进行了详细研究。利用高压气体对声源的气室充气,形成高压气体腔室,接通牵引电磁铁电路,电磁铁带动连动轴和堵头使高压气体高速喷出,高速气流在...为实现强声的气动发声,设计了一种基于喷注型和谐振型组合的复合式气动声源,仅对喷注型声源进行了详细研究。利用高压气体对声源的气室充气,形成高压气体腔室,接通牵引电磁铁电路,电磁铁带动连动轴和堵头使高压气体高速喷出,高速气流在谐振管内形成湍流,从而产生强声。仿真结果显示了湍流的产生,并可得到168 d B的强声。利用B&K 3560 Pulse多分析系统对自制的气动声源进行测试,结果显示:在距离出气口10 cm处,声压级可达146 d B,这样可推导出在距离出气口1 cm处,声压级可超过164 d B,测量结果与仿真结果较为接近。最后,对非线性声波形成的激波进行了分析。研制的强声气动声源可用作动物实验的声源。展开更多
An analytical model of acoustic field excited by a pulsed-laser line source on a coated cylinder is presented. Surface wave dispersive behaviours for a cylinder with a slow coating are analysed and compared with that ...An analytical model of acoustic field excited by a pulsed-laser line source on a coated cylinder is presented. Surface wave dispersive behaviours for a cylinder with a slow coating are analysed and compared with that of a bare cylinder. Based on this analysis, the laser-generated transient response of the perturbed Rayleigh wave and the higher modes of steel cylinder with a zinc coating are calculated from the model using residue theory and FFT technique. The theoretical result from the superposed waveform of the perturbed Rayleigh wave and higher modes agree well with the waveform obtained in experiment. The results show that the model and numerical method provide a useful technique for quantitatively characterizing coating parameters of coated cylinder by the laser generated surface waves.展开更多
文摘为实现强声的气动发声,设计了一种基于喷注型和谐振型组合的复合式气动声源,仅对喷注型声源进行了详细研究。利用高压气体对声源的气室充气,形成高压气体腔室,接通牵引电磁铁电路,电磁铁带动连动轴和堵头使高压气体高速喷出,高速气流在谐振管内形成湍流,从而产生强声。仿真结果显示了湍流的产生,并可得到168 d B的强声。利用B&K 3560 Pulse多分析系统对自制的气动声源进行测试,结果显示:在距离出气口10 cm处,声压级可达146 d B,这样可推导出在距离出气口1 cm处,声压级可超过164 d B,测量结果与仿真结果较为接近。最后,对非线性声波形成的激波进行了分析。研制的强声气动声源可用作动物实验的声源。
基金Supported by the National Natural Science Foundation of China under Grant No 10374070.
文摘An analytical model of acoustic field excited by a pulsed-laser line source on a coated cylinder is presented. Surface wave dispersive behaviours for a cylinder with a slow coating are analysed and compared with that of a bare cylinder. Based on this analysis, the laser-generated transient response of the perturbed Rayleigh wave and the higher modes of steel cylinder with a zinc coating are calculated from the model using residue theory and FFT technique. The theoretical result from the superposed waveform of the perturbed Rayleigh wave and higher modes agree well with the waveform obtained in experiment. The results show that the model and numerical method provide a useful technique for quantitatively characterizing coating parameters of coated cylinder by the laser generated surface waves.
