MURPHYS-HSFS-2014 - 7th International Workshop on Multi-Rate Processes & Hysteresis, 2nd International Workshop on Hysteresis and Slow-Fast Systems, April 7-11, 2014 - Abstract

Iyer, Ram

Investigation of Losses due to Hysteresis in Capillary Effect

Capillary action or Capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity (Wikipedia definition). Three effects contribute to capillary action, namely, adhesion of the liquid to the walls of the confining solid; meniscus formation; and low Reynolds number fluid flow. Capillary action has been studied at least since Robert Boyle in 1660, if nor earlier. Our research investigates the dissipation of energy during one cycle of capillary action, when the liquid volume inside a capillary tube first increases and subsequently decreases. Assuming quasi-static motion, we set up the equations for equilibrium of the liquid column using calculus of variations. Competing energy terms include the meniscus surface energy, adhesion energy, and volume energy due to gravitation. Numerical solution of the equations reveal the dominant cause for hysteresis losses to be the adhesion between the liquid and the wall of the solid.