Flow Characteristics in a Duct with Micro-Structured Water-Repellent Surface

摘要

The drag reduction is very important from the point of view of environmental protection. Highly water-repellent surface was reported to show the drag reduction in laminar flow of water. The cause of the drag reduction is thought that water slips on air layer held in microstructure of highly water-repellent surface. In this study, it was proved that micro-structured water-repellent surface covered with water has air layer in a hollow place by surface observation. The drag reduction measurement was carried out on micro-structured water-repellent, micro-structured no water-repellent and silicon smooth surface. In case of micro-structured water-repellent surface, the drag reduction rate was 2% at Reynolds number around 1100.