Title: Numerical Study on Drag Reduction in Parallel Plates with Water-Repellent Micro-Structure
Abstract:We have investigated the drag reduction phenomena on highly water repellent surfaces, which have micron to submillimeter order of projections. In the present study, the flow field is modeled as lamina...We have investigated the drag reduction phenomena on highly water repellent surfaces, which have micron to submillimeter order of projections. In the present study, the flow field is modeled as laminar flow between two walls and is solved only near-wall region with finite difference method. To derive the entire velocity profile and to evaluate drag reduction ratio, velocity of the center region is estimated as quadratic function of distance from wall with appropriate boundary condition. The numerical results show that 50 μm-width, 100 μm-pitch, 25μm-height square projections on the parallel plates at 2 mm distance gives 6.2% of drag reduction. Larger scale of microstructure or thinner micro-projections more drag reduction. On the other hand, air layer thickness or height of projections does not have significant influence on the degree of drag reduction.Read More