Anti-erosive mechanism of a grooved surface against impact of particle-laden flow

Abstract

Erosion is a mechanical process that determines the lifetime of many machine components, as well as the quality of the protective skins of some animals and plants. Here, we assess quantitatively the role of grooves on ductile erosive surfaces in reducing erosion caused by the impact of particle-laden flow. In particular, we focus on V-shape grooves that are much larger than the particles. The grooves can induce diversification of impingement angles, multiple impacts of a single particle, and air swirls. By measuring the erosion rates of smooth and grooved surfaces at different impingement angles, and imaging the particle motion with a high-speed camera, we show that the diversified impingement angle on the grooves plays a key role in reducing erosion. Further, we predict theoretically the optimal groove angle for maximal erosion reduction at different values of impact angle. Our findings provide a framework for the design of artificial anti-erosive surfaces and advance our understanding of the design principles that enable biological skins to display anti-erosive properties when subjected to particle-laden fluid streams.