Lattice Boltzmann simulation of liquid flow characteristics of hydrophobic surfaces

The influence of microcosmic topography on the surface wet ability is investigated using a lattice Boltzmann method, and then the liquid flow over hydrophobic surfaces with microcosmic topography is simulated in a micro channel. From aspect of normal velocity, shear stress and slip velocity, the flow field characteristics of hydrophobic surfaces are analyzed and the generation mechanism of hydrophobic surface's slip flow is revealed. The simulation results show that hydrophobic surfaces'slip flow is caused by the low surface energy effect and microcosmic topography together. Hydrophobic surfaces with microcosmic topography have a better drag reduction effect than smooth hydrophobic surfaces. The reason is that the microcosmic topography can retain gas and generate gas-liquid free shear surfaces, which can enhance hydrophobic surfaces'slip flow and make the maximum slip velocity reach about 50% of the average speed of mainstream.