Stability and drag reduction mechanism of mucus-water interface on underwater vehicle surface.

This article investigates the drag reduction mechanism and stability of the mucus–water interface inspired by marine fish skin, focusing on how physical and mechanical parameters—such as water flow rate, mucus discharge velocity, mucus pore diameter, mucus viscosity, and interfacial tension—affect the interface’s stability and drag reduction performance. Using computational fluid dynamics simulations based on the level set method and experimental setups including a microinterfacial stability observatory and a water-tunnel facility, the study finds that increased mucus discharge velocity, larger pore diameter, higher mucus viscosity, and greater interfacial tension enhance interface stability and slip length, thereby improving drag reduction; however, higher water velocities reduce stability and drag reduction efficiency. The synergistic effect of mucus and microstructured surfaces achieved up to approximately 30% drag reduction experimentally, highlighting the importance of balancing mucus viscosity to optimize performance. The research provides foundational insights for developing bioinspired underwater drag reduction technologies applicable to vehicles and ships, while noting that further studies are needed to optimize mucus discharge configurations and retention for practical engineering applications.