The acoustic propagation characteristics of the cavitating flow are essential for the noise suppression, but were not well studied. In the current paper, a new technique concerning the propagation path of the monopole acoustic energy is presented and two typical thermodynamic cavitation modes (the inertial and thermal modes) are selected to investigate the effect of the cavity shedding dynamics on the acoustic propagation path. In the inertial mode, the temporal variation and the spatial distributions of the monopole acoustic energy as well as the divergence of the monopole acoustic pressure are both more powerful and concentrated than that in the thermal mode. The acoustic propagation path in the thermal mode strictly satisfies the feature of the convective amplification, while there exists another propagation direction close to the normal direction of the foil surface in the inertial mode. Furthermore, the occurrence of the normal direction propagation will make the path deviate from the convective direction.

空化流的声传播特性对于噪声抑制至关重要，但尚未得到很好的研究。在本文中，提出了一种关于单极声能传播路径的新技术，并选择了两种典型的热力学空化模式（惯性和热模式）来研究空腔脱落动力学对声传播路径的影响。在惯性模式中，单极声能的时间变化和空间分布以及单极声压的发散都比热模式更强大和集中。热模声传播路径严格满足对流放大特性，而在惯性模式下，靠近箔面法线方向存在另一个传播方向。此外，法线方向传播的发生会使路径偏离对流方向。