1. Increase the roughness of the metal plane: When liquid or gas flows over the metal surface, the roughness of the surface will make it form more eddies and turbulence, thus increasing the flowing water area. Therefore, the roughness of metal plane can be increased by grinding and sandblasting to increase its flowing water area.

2. Increase the surface area of the metal plane: increasing the surface area of the metal plane can make the liquid or gas stay on its surface for a longer time, thus increasing the running water area. The surface area of metal can be increased by adding fine structure and uneven surface.