Guo Chunfang, Liu Lei, Liu Changwan
College of Mechanical Engineering, Donghua University, Shanghai 201620, People's Republic of China.
J Phys Condens Matter. 2021 Dec 10;34(9). doi: 10.1088/1361-648X/ac3c67.
Regulating the impact dynamics of water droplets on a solid surface is of great significance for some practical applications. In this study, the droplet impingement on a flexible superhydrophobic surface arrayed with micro-scale grooves was investigated experimentally. The surface was curved into cylindrical shapes with certain curvatures from two orthogonal directions, where axial and circumferential grooves were formed, respectively. The effects of curvature diameter and Weber number, as well as the orientation of grooves on droplet spreading and retracting dynamics were analyzed and explained. Results show that the circumferential grooves promote the spreading of a droplet in the azimuthal direction, where the droplet rebounds from the surface with a stretched shape. This mechanism further reduces the contact time of impacting droplets on the superhydrophobic surface compared to the other curving mode.
调控水滴在固体表面的冲击动力学对于一些实际应用具有重要意义。在本研究中，对水滴冲击排列有微尺度凹槽的柔性超疏水表面进行了实验研究。该表面从两个正交方向弯曲成具有一定曲率的圆柱形状，分别形成轴向和周向凹槽。分析并解释了曲率直径、韦伯数以及凹槽方向对液滴铺展和回缩动力学的影响。结果表明，周向凹槽促进液滴在方位角方向铺展，液滴以拉伸形状从表面反弹。与其他弯曲模式相比，该机制进一步减少了冲击液滴在超疏水表面的接触时间。
