NUMERICAL SIMULATION OF THE MOTION OF DROPS ON AN INCLINED SURFACE

Abstract

The flow of two-dimensional drops suspended in an inclined channel is studied bynumerical simulations at non-zero Reynolds numbers. The flow is driven by the acceleration dueto gravity, and there is no pressure gradient in the flow direction. The equilibrium position of adrop is studied as a function of the Reynolds number, the Capillary number, the inclination angleand the density ratio. It is found that the drop always lags the undisturbed flow. More deformabledrops reach a steady state equilibrium position that is farther away from the channel floor. Fordrops that are heavier than the ambient fluid, the equilibrium position moves away from thechannel floor as the Reynolds number is raised. The same trend is observed when the inclinationangle with respect to horizontal direction increases. The behavior agrees with computationalmodeling of chute flow of granular materials. A drop that is lighter than the ambient fluid reachesa steady state equilibrium position closer to the channel floor when the Reynolds number orinclination angle increases. Simulations of 40 drops in a relatively large channel, show that dropsmove away from the channel floor when the density ratio is larger than unity.