Stefan adhesion explained

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) : F = (3 \pi η R ^{4})/(2 h ^{3}) (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.^[1] In addition, these systems are much more complex when the fluid is non-Newtonian or inertial effects are relevant (high flow rate).

Notes and References

1. Smith AM. The Structure and Function of Adhesive Gels from Invertebrates.. 2002 . Integr. Comp. Biol. . 42 . 6 . 1164–1171 . 10.1093/icb/42.6.1164 . 21680401. free .