On the path to an optoacoustic hearing implant for stimulation of residual hearing, one possibility for tone generation in liquids is the concatenation of acoustic click events, which can be realized i. a. by the acoustic transients that accompany an optical breakdown. The application of a viscous gel is helpful in this context, as this results in an attenuation of the distortion of tone quality caused by higher harmonic components. To further understand the underlying cavitation bubble dynamics both in the viscous gel and in a confined volume that is dimensioned similarly to the human cochlea, a numerical model built in OpenFOAM was adapted and compared to additional experiments. Experimentally, the acoustic transients were generated by optical breakdown by nanosecond laser pulses with a pulse duration of 0.7 ns and a wavelength of 1064 nm. The pulses were focused on a viscous gel inside a water container. The pressure transients were measured by a needle hydrophone. The comparison of the bubble dynamics in different viscosities between the model and the experiment shows that, except for high viscosities, the experimental observations could be modeled by the simulation. We assume that the maximum size of the cavitation bubble strongly decreases with increasing viscosity, which can be used for high-frequency attenuation as reported in our previous research. In conclusion, this study aims at an application-oriented realization of the numerical cavitation bubble dynamics model to understand the experimental findings on the pathway to an optoacoustic hearing implant.

在用于刺激残余听力的光声听力植入物的道路上，在液体中产生音调的一种可能性是声学咔嗒声事件的串联，这可以通过伴随光学击穿的声学瞬变来实现。在这种情况下，粘性凝胶的应用是有帮助的，因为这会导致由高次谐波分量引起的音质失真的衰减。为了进一步了解粘性凝胶和尺寸与人类耳蜗相似的有限体积中潜在的空化气泡动力学，我们对 OpenFOAM 中构建的数值模型进行了调整，并与其他实验进行了比较。实验上，声瞬变是通过脉冲持续时间为 0.7 ns、波长为 1064 nm 的纳秒激光脉冲的光学击穿产生的。脉冲聚焦在水容器内的粘性凝胶上。压力瞬变由针状水听器测量。模型与实验之间不同粘度下气泡动力学的比较表明，除了高粘度之外，实验观察结果可以通过模拟来建模。我们假设空化气泡的最大尺寸随着粘度的增加而强烈减小，这可用于我们之前研究中报道的高频衰减。总之，本研究旨在以应用为导向实现数值空化气泡动力学模型，以了解光声听力植入途径的实验结果。