摘要:
常规的近场声全息均是采用全息面声压或质点振速作为输入量求解,由于采用单一输入量无法分离来自全息面背向声波的干扰,因此要求所有声源均位于全息面的同一侧,即测量声场为自由声场,这种要求大大限制了近场声全息的实际应用.基于声压-速度测量的近场声全息以全息面上声压和质点振速同时作为输入量,通过建立和求解两侧声源在全息面上的声压和质点振速耦合关系,可以实现全息面两侧声波的分离,从而解决上述问题.文中在前期对声场分离技术研究的基础上,基于欧拉公式和有限差分近似,推导了新的基于声压-速度测量的平面近场声全息理论公式.随后通过实验检验了该方法在有背景源干扰情况下实现声场分离和重建的有效性.
Abstract:
In the conventional nearfield acoustic holography (NAH), only the pressure or particle velocity is used as the input quantity, and it cannot separate the waves from the two sides of the hologram surface. Therefore, all sources are assumed to be on one side of the hologram surface, i.e. the sound field is assumed to be free. This assumption limits the practical applications of NAH. In the NAH using pressure and particle velocity measurements, both pressure and particle velocity are used as the input quantities. By establishing and solving the coupling relationship on the hologram surface between the waves from the two sides of the hologram surface, the waves from the two sides can be separated. On the basis of the previous studies on sound field separation techniques and based on the Euler formula and the finite difference approximation technique, a new theoretical formula of NAH using pressure and particle velocity measurements is given, and then an experiment is performed to validate the method.