Abstract
It is well known as the wringing phenomenon of gage blocks that a strong adhesive force appears between two smooth surfaces when a thin liquid film is applied on the interface. A theoretical and experimental study is conducted to discuss the wringing mechanism. The liquid film may be separated into a large number of small puddles when two surfaces are rubbed together. One can expect a large adhesive force due to the resultant of surface tension acting on the circumference of each puddle. Numerical results for oil distribution between two surfaces show that the total perimeter length of liquid film reaches 10500 m on the surface of 3cm2, which leads to 1.0×106 (N/m2) for the adhesive force. The adhesive forces measured experimentally roughly agree with the theoretical value. A simple model is proposed to explain the adhesive force dependence on the velocity of pulling apart two surfaces.
