Abstract:Based on the high speed visual imaging experimental platform,the experimental study of droplets impact on a hydrophobic spherical surface is conducted.The dynamic behaviors of the droplet impact process are observed and quantitatively characterized,and the effects of the droplet impact velocity and the droplet-sphere diameter ratio on the droplet impact behavior characteristics are analyzed.The experimental results show that the impact process can be divided into three stages:spreading,retraction and oscillation.The droplets spread evenly around the contact point after contacting the spherical surface,then retract after reaching the maximum spreading diameter.Subsequently,the droplet undergoes multiple spreading-retraction stages during the oscillation process.Until the kinetic energy and the surface energy reach an equilibrium state,the droplet tends to be stationary on the spherical surface.The increase in the droplet impact velocity increases the inertial force,which promotes the spreading of the droplet,which increases the time required for the droplet to reach stable state.In addition,the droplet-sphere diameter ratio has less influence on the droplet impact behavior characteristics.