Study on the fluid flow characteristic inside bionic surface texture serving in flooded tribo-contacts

Purpose Inspired by the climbing capabilities of tree frogs and salamanders on wet substrates, this study aims to explore the liquid migration dynamics within microchannels on bionic textured surfaces. Design/methodology/approach Surface textures with different geometric configurations were fabricated on poly(methyl methacrylate) substrates, and their fluid flow characteristic was observed in situ. The effects of texture type, area ratio and groove depth on flow efficiency were systematically evaluated through parametric studies. Findings The flow behavior of liquid within microchannels is strongly influenced by the geometric parameters of bionic surface textures. Circular and hexagonal surface textures demonstrate excellent flow efficiency, owing to their relatively smooth structural features that prevent excessive vortex formation and reduce flow resistance. An increase in area ratio (32%–62%) was found to expand the high-speed flow zone while suppressing vortex formation, thereby enhancing liquid flow efficiency. As the texture groove depth (0.5–5 mm) increases, although the vortex region decreases, the influence of the high-velocity region becomes dominant, leading to a significant reduction in the overall flow velocity. Originality/value These findings offer valuable insights for optimizing surface texture designs to enhance flow efficiency, which is critical for applications requiring high friction and adhesion under wet conditions, such as rubber tires, soft robotics and medical devices.