The unstable detachment of cloud cavitation has a profound impact on the safe operation of hydraulic machinery. This study aims to elucidate the relationship between cavitation structures and cavitation erosion, with particular attention to how slits affect the periodic characteristics of unstable cloud cavitation. The results indicate that the interaction between the high-speed jet from the slit and the main flow generates leakage vortex cavitation, which subsequently merges with the main cavitation zone, resulting in complex cavitation phenomena. The high-speed jet from the slit markedly diminishes the momentum of the re-entrant jet, consequently suppressing the complete detachment of the attached cavitation. This leads to secondary development of the attached cavitation and reduces the primary frequency of cavitation pulsations by 48.5 %. Additionally, the detached cloud cavitation is smaller in scale and collapses more rapidly. Furthermore, this study performed cavitation erosion experiments on hydrofoil made from three different materials, finding that PU-coated material demonstrates considerable resistance to cavitation erosion. Notably, vortex cavitation collapse and rebound near the slit can cause significant erosion on the surface of the hydrofoil.

中文翻译：

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狭缝水翼的空蚀形态与侵蚀


云空化的不稳定脱离对水力机械的安全运行有着深远的影响。本研究旨在阐明空化结构与空化侵蚀之间的关系，特别关注狭缝如何影响不稳定云空化的周期性特征。结果表明，狭缝高速射流与主流相互作用产生漏涡空化，随后与主空化区融合，产生复杂的空化现象。来自狭缝的高速射流显着减弱了再入射流的动量，从而抑制了附着空化的完全脱离。这导致附着空化的二次发展并使空化脉动的初级频率降低48.5%。此外，脱离的云空泡规模更小，崩塌速度更快。此外，本研究对三种不同材料制成的水翼进行了空蚀实验，发现 PU 涂层材料表现出相当大的抗空蚀能力。值得注意的是，狭缝附近的涡流空化崩溃和反弹会对水翼表面造成严重侵蚀。