Viscosity in air-gun bubble modeling

Abstract

I have presented finite volume simulations of an air-gun bubble in which the compressible Navier-Stokes equations were solved numerically. These equations included viscosity. My simulation also applied the no-slip condition at the bubble surface. The effects of the viscous terms were small; however, the effect of the no-slip condition was significant, causing a reduction in the bubble rise rate of 18.1% and an increase in the collapse pressure of 17.9%. The no-slip condition caused boundary layers at the bubble surface and changes in the velocity structure throughout the bubble. The no-slip condition allowed the effect of skin-friction drag on the bubble to be captured, along with Kelvin-Helmholtz instabilities at the surface, which caused a change in the shape of the bubble during collapse. The influence of the no-slip condition suggests that it is important and should be included in air-gun bubble models.