Clausthal University of Technology, Institute of Applied Mechanics, Adolph-Roemer-Straße 2A, 38678 Clausthal-Zellerfeld, Germany.
University of Göttingen, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
Ultrason Sonochem. 2022 Sep;89:106060. doi: 10.1016/j.ultsonch.2022.106060. Epub 2022 Jun 9.
A model for acoustic cavitation flows able to depict large geometries and time scales is proposed. It is based on the Euler-Lagrange approach incorporating a novel Helmholtz solver with a non-linear acoustic attenuation model. The method is able to depict a polydisperse bubble population, which may vary locally. The model is verified and analyzed in a setup with a large sonotrode. Influences of the initial void fraction and the population type are studied. The results show that the velocity is strongly influenced by these parameters. Furthermore, the largest bubbles determine the highest pressure amplitude reached in the domain, which corresponds to the Blake threshold of these bubbles. Additionally, a validation is performed with a small sonotrode. The model reproduces most of the experimentally observed phenomena. In the experiments, neighboring bubbles are found which move in different directions depending on their size. The numerical results show that the responsible mechanism here is the reversal of the primary Bjerknes force at a certain pressure amplitude.
提出了一种能够描述大尺寸和长时间尺度的空化流模型。它基于欧拉-拉格朗日方法，结合了一种新的亥姆霍兹求解器和一种非线性声衰减模型。该方法能够描述局部变化的多分散泡群。在一个带有大超声变幅杆的装置中对模型进行了验证和分析。研究了初始空泡分数和种群类型的影响。结果表明，这些参数对速度有很大的影响。此外，最大的气泡决定了域中达到的最高压力幅值，这对应于这些气泡的 Blake 阈值。此外，还使用小超声变幅杆进行了验证。该模型再现了大多数实验观察到的现象。在实验中，发现了相邻的气泡，它们根据大小向不同的方向移动。数值结果表明，这里的原因机制是在一定的压力幅值下，主 Bjerknes 力的反转。
