Analysis of flow and heat transfer inside oscillatory squeezed thin films subject to a varying clearance

The flow and heat transfer inside a non-isothermal and incompressible thin film having its upper plate slightly inclined from the horizontal and undergoing an oscillatory squeezing motion is investigated in this work. Two models are analyzed: low and large Reynolds number flow models. The corresponding governing equations for each model are properly non-dimensionalized and solved numerically. The main controlling parameters for the dynamic and thermal behavior of the inclined thin film are found to be the amplitude of the upper plate motion, squeezing Reynolds number, squeezing number, thermal squeezing parameter and the dimensionless slope of the upper plate. It is found that fluctuations in the axial and normal velocities are greater for convergent thin films than for divergent thin films. Furthermore, Nusselt numbers and their amplitudes are found to decrease with an increase in the dimensionless slope of the upper plate. Finally correlations are obtained for Nusselt numbers and their corresponding amplitudes for two different thermal conditions: constant wall temperature and uniform wall heat flux.