Cavitation induced wall loads at an ultrasonic horn facility are analyzed by 3D flow simulations and temporally high-resolved pressure measurements for varying gap widths between horn and stationary erosion specimen. Piezoelectric polyvinylidene fluoride (PVDF) probes are placed at different radial wall positions at the stationary specimen opposite of the oscillation horn and yield a declining flow aggressiveness with increasing radial position and gap width. The measurement results are reproduced by virtual probes in CFD simulations. Pressure measurement results yield a measure of flow aggressiveness in terms of wall load collectives that correlate well with incubation times obtained by erosion tests. A maximum aggressiveness at the specimen at 0.5mm gap width is obtained. Subharmonic frequencies associated with horn-attached void cavities increase with gap width which is well captured by the simulation. Due to the revealing of 3D flow patterns by the validated CFD results, detailed flow mechanisms associated with flow aggressiveness are discussed. The subharmonic frequency characteristics vs. gap width is associated with the shielding of the inner attached cavity region for small gaps and prevents the cavity from subharmonic collapse for several horn cycles. This shielding is less pronounced for larger gaps and leads to a shorter life time of the attached cavity and therefore to higher subharmonic frequencies.

中文翻译：

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3D流动模拟和压力测量，用于评估间隙宽度不同的超声腐蚀设备中的气蚀动力学和流动侵蚀性。

通过3D流动模拟和时变高分辨压力测量来分析超声变幅杆装置上空化引起的壁载荷，以测量变幅杆和固定侵蚀试样之间的间隙宽度。压电聚偏二氟乙烯（PVDF）探头放置在振动喇叭对面的固定样品的不同径向壁位置处，随着径向位置和间隙宽度的增加，流动侵蚀性下降。测量结果通过CFD模拟中的虚拟探针重现。压力测量结果以壁负荷的总和来衡量流动侵蚀性，该负荷与侵蚀测试获得的孵育时间密切相关。在间隙宽度为0.5mm时获得最大的试样侵略性。与牛角连接的空洞相关的次谐波频率会随着间隙宽度的增加而增加，这可以通过仿真很好地捕获。由于通过验证的CFD结果揭示了3D流动模式，因此讨论了与流动性相关的详细流动机制。次谐波频率特性与间隙宽度的关系与对内部间隙区域的较小间隙的屏蔽相关联，并在数个喇叭周期内防止腔发生次谐波崩溃。对于较大的间隙，这种屏蔽不太明显，并且会导致所附着的腔体的使用寿命缩短，从而导致更高的次谐波频率。次谐波频率特性与间隙宽度的关系与对内部间隙区域的较小间隙的屏蔽相关联，并在数个喇叭周期内防止腔发生次谐波崩溃。对于较大的间隙，这种屏蔽不太明显，并且会导致所附着的腔体的使用寿命缩短，从而导致更高的次谐波频率。次谐波频率特性与间隙宽度的关系与对内部间隙区域的较小间隙的屏蔽相关联，并在数个喇叭周期内防止腔发生次谐波崩溃。对于较大的间隙，这种屏蔽不太明显，并且会导致所附着的腔体的使用寿命缩短，从而导致更高的次谐波频率。