Effect of surface curvature on drop impact forces on curved superhydrophobic surfaces

초록

The dynamic impact of liquid drops on rigid surfaces can be found in numerous practical applications, including spray cooling, inkjet printing, spray coating, airplane wings, and steam turbine blade. Notably, the post-impact dynamics can affect the robustness and durability of the impacted surfaces by causing erosion or degradation. This study experimentally and numerically investigates the impact forces on cylindrically curved superhydrophobic (C-SHPo) surfaces across a wide range of Weber number (We = 50 − 175) and cylinder diameter (3 − 20 mm). The results show two distinct peaks in the impact force: the one originating from the inertial impact of the drop and the other from the pressure rise during the retraction motion. Initial peak force increases with We owing to higher inertial effect, whereas the second peak force shows unexpected behavior on small C-SHPo surfaces: the second peak force increases with We first then it decreases again if We is greater than the certain Weber numbers. Based on the three-dimensional direct numerical simulation, it is found that the reduced contact area resulted from the detached and fingered parts of drop plays a major role in the reduced second peak force on small C-SHPo surfaces. © 2025 Elsevier Ltd

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