Oblique water entry of micron particles

Water entry problem has attracted much interest in the past century, but few research focused on the oblique water entry of micron particles, which is very common in nature and industrial processes. The oblique water entry of micron PMMA particles with different impact angles is realized by a self-made impactor and observed with a high speed camera. It was found that the distortion of the liquid surface after impact is non-axisymmetric due to the lateral velocity of the particle, and the wetted part of the particle surface is not axisymmetric along the impact direction, which produces a force perpendicular to the impact direction and makes the particle’s motion direction changes during the water entry process. The critical velocity for the particle to sink increases with the decrease in impact angle. A simple model is established to analyze the energy balance during the critical sinking process and the expression of the critical sinking velocity is given, which agrees well with our experimental results.