Effect of Acceleration of the Cylindrical Rod on the Gas-Liquid Interface Shape near the Rod Surface

To elucidate the dynamic contact angle behavior in the transient state of the contact line motion, we conducted experimental investigations in which the cylindrical rod vertically intersecting the liquid surface was immersed with constant acceleration into the liquid and captured images of the meniscus. We found that the contact angles just after the initiation of the motion of the rod deviates from those measured with constant immersing velocity of the rod. The deviation is found to continues until the capillary number increased up to a certain value, which can be expressed as a form of Ca*mRen, with Ca* modified capillary number, Re Reynolds number, m and n fitting coefficients.