A Numerical Study on the Effect of Various Forces on Rising Bubble in a Confinement
摘要
In present numerical study we look at the effect of different forces on dynamics of a rising bubble in a confined channel with no external pressure gradient in incompressible flow regime. This study is conducted for five different cases. With surface tension (S.T.), buoyancy and viscosity dominance effects as primary cases followed by two other cases where combination of buoyancy with S.T. and viscosity with S.T. are considered to be dominating. It is observed that the rise of bubble, when it flows close to wall in a channel, is greatly affected by strength of competing inertial and surface tension forces along with shear exerted by walls. The simulations are performed using an in-house Navier-Stokes solver coupled explicitly with Level Set advection and a Re-initialization procedure. The flow solver uses first order upwind convective scheme with implicit Euler time stepping in SIMPLE algorithm for pressure velocity coupling. Converged velocities thus obtained are passed to Level Set advector which uses WENO-5 with RK-4 time stepping in explicit fashion. The advected level set function is then passed to Re-initialization subroutine which uses WENO-5 and TVD RK-3 scheme for discretization of Re-initialization equation recursively till steady state is reached. In our method, surface tension has been added as a body force on Collocated grid point directly.