Abstract
The drag reduction of water flow on a finely meshed metal surface was experimentally investigated, in order to examine the effects of the air trapped on a hydrophobic surface with microstructures. A meshed stainless steel plate with circular holes (thickness: 50μm, hole diameter: 140μm, surface void fraction: 49%) was used as the bottom wall of a rectangular cross section test channel. The existence of the air in the mesh holes was controllable by filling a chamber beneath the plate with either air or water. The friction factor was measured in the turbulent regime (Reynolds number: 6000〜12000), for "dry" and "wet" states of the mesh surface. The results showed that a 25〜30% reduction of the friction factor compared to a smooth surface was obtained by the meshed surface with the air held in the mesh holes.
