Numerical investigation of water droplet impact on horizontal beams

Droplet impact on elastic beams is considered as a novel model of energy transfer which is a promising alternative in applications of energy harvesting. The transient impact process is dominated by the fluid–solid interaction and the capillary effect. The numerical model based on SPH method allows predicting the droplet dynamic behaviors due to super-hydrophobic (SH) surfaces. The predicted results are also compared with relevant experiments to verify the robustness and flexibility of the model. For fixed-fixed beams, typical regimes, namely spherical-shaped rebound, pancake-shaped rebound and splashing of droplet, are identified. The elasticity of beam causing the earlier lifting-off phenomenon of droplet is investigated in detail. By comparison, cantilever beams repel the droplet in a smoother way and large deformation of the beam is considered. The slipping-off phenomenon is expected to occur under specific conditions on soft cantilevers. The effect of elasticity plays a key role in the maximum deflection and oscillating frequency for both types of beams. This work examines the effectiveness of the framework based on the numerical model which provides further understandings for droplet impacts. It may lay the foundation for practical applications, such as engineering piezoelectric raindrop energy harvesters and plant leaves repelling raindrops.