Simulating flow field of superhydrophobic surface in laminar flow to reduce its drag

To our knowledge, there is almost no paper in the open literature dealing with what is mentioned in the title. Taking into account the micro-structural characteristics of a superhydrophobic surface, we use the Cassie model and the volume of fluid (VOF) model to simulate its flow field in the laminar flow between two infinitively large plates. To do so, we apply structural grids to dividing the computing domain. Then we analyze the drag reduction characteristics of the superhydrophobic surface in terms of velocity distribution, pressure distribution, slide velocity and drag reduction rate. The simulation results, given in Figs. 4 through 17, and their analysis show preliminarily that: (1) there is pressure difference drag near the groove of the superhydrophobic surface, producing a low-speed whirlpool inside the groove and both the thrust effect and the vortex cushion effect; (2) the drag reduction rate of the superhydrophobic surface increases with increasing width of the groove, decreases with increasing space between grooves and increases with increasing flow velocity, but does not increase with increasing depth of the groove; (3) the rectangular groove is more effective for drag reduction than both the V-shape groove and the U-shape groove.