中文摘要：

利用实验的方法研究了涂层对绕水翼空化流动特性的影响。分别针对喷涂环氧涂层和氟碳涂层的 Clark-Y 型水翼，采用高速摄像装置观察了不同空化阶段的空化流动形态。研究结果表明：（1）在初生空化阶段，当σ=1.82时，沿环氧涂层水翼表面展向排列着初生空泡，而氟碳涂层水翼还处于无空化状态，说明相对于环氧涂层，氟碳涂层对空化现象的产生有一定的抑制作用，氟碳涂层水翼初生空化数为1.50；（2）在片状附着型阶段，当σ小于1.63时，绕环氧涂层水翼的空化先于氟碳涂层水翼发展至片状空化，绕水翼空化流动产生大量分散空泡，沿水翼表面向后运动过程中逐渐长大，在高压区溃灭后形成小空泡并以马蹄涡形式继续运动。同一空化数下，绕环氧涂层水翼空化流动的空泡长度大于氟碳涂层水翼。但随空化数降低，两者空泡长度逐渐接近，说明环氧涂层在片状空化阶段对空化的抑制作用逐渐增强；（3）σ=0.87时空化发展至云状空化阶段，空化流动伴随周期性的云状空泡的脱落，绕环氧涂层水翼的空化流动周期及无量纲空化面积均小于氟碳涂层水翼，说明涂层对空化的非定常变化也有一定的抑制作用，且环氧涂层强于氟碳涂层。

英文摘要：

Influence of surface coatings on cavitating flow around hydrofoils is studied experimentally. Hy-drofoils are painted with epoxy coating and fluorocarbon coating, respectively. High speed visualization sys-tem is used to observe the cavitation flow patterns in different stage. The results show three main phenome-na. Firstly, in stage of incipient cavitation, obvious cavities occur in form of bubbles dispersal along spanwise direction on the suction side of hydrofoil coated by epoxy when σ=1.82, while no cavitation occurs around fluorocarbon hydrofoil. So the fluorocarbon coating is helpful in restrict on the occurrence of cavitation. The incipient cavitation number for fluorocarbon hydrofoil is 1.50. Secondly, in stage of attached sheet cavita-tion, cavitating flow around fluorocarbon hydrofoil develops into sheet cavitation when σ small than 1.63, which is earlier than that of epoxy foil. The cavitating flow consists of clusters of dispersive bubbles and cavi-ties become larger and move along the surface of foil. The bubbles collapse in high pressure region and keep moving downstream in form of many horseshoe vortexes. With same σ, the cavity length along surface of the epoxy hydrofoil is relatively larger than fluorocarbon hydrofoil. But cavity length around epoxy hy-drofoil and fluorocarbon hydrofoil are equal almost with decreasing of σ. Restricting effect of epoxy coating on cavitation becomes stronger gradually in sheet cavitation stage. Thirdly, the cavitating flow develops into cloudy cavitation with periodical shedding of cloudy bubbles when σ=0.87. Both period of cavitating flow and non-dimensional cavity area for epoxy hydrofoil are smaller than that of fluorocarbon hydrofoil. Restriction on unsteady development of cavitation generated by epoxy coating is stronger than fluorocarbon coating.