粗糙圆柱水平入水的界面流动分离特性试验研究

An experimental research on the rough surface cylinders with different micron particle sizes falling into water is carried out. By means of high-speed photography, the geometry and motion of the interface flow on the cylindrical surface after the entry at different initial speeds are studied. The location of the flow separation was measured accurately. The result shows that the serrated instability can be observed at the three-phase contact line, the velocity of the three-phase contact line decreases and the liquid surface is easier to be separated from the rough surface cylinder. Secondly, several factors on the separation are studied. It is found that with the surface roughness decrease, the distance from the separation position to the bottom base of the cylinder increases first and then decreases; with the falling velocity increase, the separation of the solid-fluid interaction becomes easier and the separation position approaches more to the bottom base. Finally, the contact angle of different rough surfaces are measured, the correlation between the hysteresis characteristics of dynamic contact angles and the separation position is studied.