This study presents results of experiments where roughness applications are evaluated in delaying the tip vortex cavitation inception of an elliptical foil. High-speed video recordings and laser doppler velocimetry (LDV) measurements are employed to provide further details on the cavitation behavior and tip vortex flow properties in different roughness pattern configurations. The angular momentum measurements of the vortex core region at one chord length downstream of the tip indicate that roughness leads to a lower angular momentum compared with the smooth foil condition while the vortex core radius remains similar in the smooth and roughened conditions. The observations show that the cavitation number for tip vortex cavitation inception is reduced by 33% in the optimized roughness pattern compared with the smooth foil condition where the drag force increase is observed to be around 2%. During the tests, no obvious differences in the cavitation inception properties of uniform and non-uniform roughness distributions are observed. However, the drag force is found to be higher with a non-uniform roughness distribution.

这项研究提出了实验结果，其中评估了粗糙度应用在延迟椭圆形箔的尖端涡流空化开始之前的评估。高速视频记录和激光多普勒测速（LDV）测量用于提供有关在不同粗糙度模式配置下的气蚀行为和尖端涡流特性的更多详细信息。在尖端下游一弦长处的涡流芯区域的角动量测量结果表明，与光滑箔条件相比，粗糙度导致较低的角动量，而在光滑和粗糙化条件下，涡流芯半径保持相似。观察结果表明，与观察到的阻力增加约2％的光滑箔片条件相比，在最佳粗糙度模式下，尖端涡旋空化开始的空化数减少了33％。在测试过程中，没有观察到均匀和不均匀粗糙度分布的空化开始特性的明显差异。然而，发现具有不均匀的粗糙度分布的阻力更高。