Numerical simulation of gas driven waves in a liquid film

Long nonlinear two-dimensional traveling waves on a liquid film driven by laminar flow of a gas with much smaller density and viscosity are investigated. The gas flow is assumed to be pressure driven. The method of particles for incompressible flow is used to solve Navier-Stokes equations. The influence of layer depth ratio, gas Reynolds number, and wavelength on wave amplitude and phase speed is studied and compared to the corresponding characteristics of gravity-capillary waves. The waves with equal amplitude but different phase speeds have been revealed, i.e., the phase speed of the gas driven waves is not always a single valued function of their amplitude. Self-similarity of velocity profiles in shear driven waves has also been demonstrated. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3053827]