Squeezing flows occur in a variety of industrial applications, including lubrication, printing, and sheet molding. Squeezing flow also occurs in the region between two bubbles growing in a foaming liquid. An experiment designed to study squeezing flow has been designed, and data indicate that the force-time behavior cannot be modeled using purely viscous, non-Newtonian constitutive equations. The force resisting squeezing first rises above the purely viscous level, and then falls below the viscous level as time increases.
Mathematical models of squeezing flows have been examined, and analytical solutions based on lubrication theory have been evaluated through comparison to numerical solutions based on the finite element method. It appears that a model based on lubrication theory, using the known kinematics of a power law viscous fluid, but using Wagner’s viscoelastic fluid for the stresses, predicts the behavior of force-time curves in qualitative agreement with the observations for strongly elastic fluids.