Stefan adhesion

Stefan adhesion is the normal stress (force per unit area) acting between two discs when their separation is attempted. Stefan's law governs the flow of a viscous fluid between the solid parallel plates and thus the forces acting when the plates are approximated or separated. The force F resulting at distance h between two parallel circular disks of radius R , immersed in a Newtonian fluid with viscosity η , at time t , depends on the rate of change of separation d h d t  :

Stefan adhesion is mentioned in conjunction with bioadhesion by mucus-secreting animals. Nevertheless, most such systems violate the assumptions of the equation In addition, these systems are much more complex when the fluid is non-Newtonian or inertial effects are relevant (high flow rate).