移動壁面上での液滴浮遊における動粘度と表面張力の影響

抄録

Effect of viscosity and surface tension on a levitating droplet over a moving wall are experimentally investigated. We measure levitation duration by changing wall velocity, droplet viscosity and surface tension. We construct a new experimental setup to expand the ranges of experimental condition. By using the new setup, we successfully levitate silicone oil droplets of 1-5 cSt. It is found that droplets levitate with wall velocity which is over a critical wall velocity. The critical wall velocity depends on viscosity of droplets, especially for low viscous regime. The critical wall velocity increases with decrease in droplet viscosity to obtain sufficiently relative wall velocity which is difference between the wall velocity and surface velocity of droplets. Surface tension also affects the critical wall velocity. To levitate high surface tension droplets, high wall velocity is required. We discuss the mechanism with considering area of an air film between the levitating droplet and the wall.