Numerical Simulation Study on the Directional Transportation of Lubricating Oil Induced by Bionic Concave and Convex Structures

We use computational fluid dynamics (CFD) simulations to clarify that geometric microstructures can affect the directional transportation of lubricating oil and analyse its transportation mechanism. Two types of geometric microstructures were designed: concave (Open Cylindrical Groove Surface and Cylindrical Groove and Spherical Pit Surface) and convex (Inclined Trapezoidal Surface, Cactus Spine‐Inspired Inclined Surface, and Araucaria Leaf‐Inspired Surface). The CFD method was employed to analyse the lubricating oil transport on these structures. Additionally, 3D printing experiments were conducted on the Araucaria Leaf–Inspired Surface (ALIS) structure for verification. The research findings indicate that in concave structures, lubricating oil transport depends more on groove shape, while in convex ones, it is due to gaps between adjacent rows. Vertically, the wedge‐shaped cavity of ALIS generates a larger Laplace pressure, allowing the oil to reach a 24.6 mm height in 20 s. Adjusting the area occupancy of ALIS from 43.8% to 50.7% increases the transport height, which peaks at 50.7% and then drops. The comparison of 3D printing and simulation strongly validates the CFD method, as their heights and states are highly consistent.