Direct numerical simulation of rising bubble with path instability

Abstract

Present research is focused on combining High- Performance Computing (HPC) and Direct Numerical Simulation (DNS) of two-phase flows, to study the dy- namic behavior of rising bubble whit path instabilities with moderate/high Reynolds numbers ( Re > 1000 ). The Navier-Stokes equations are discretized us- ing the finite-volume approach; the pressure-velocity coupling is solved using a fractional-step projec- tion method, whereas the conservative level-set (LS) methodology is used for interface capturing. Thus, mass conservation issue that is known to affect stan- dard LS methods is circumvented. Moreover, the spa- tial discretization of the computational domain em- ploys an Adaptive Mesh Refinement (AMR) strategy for the reduction of computational resources. In this work, buoyancy bubbles rising in the wob- bling regime are researched at Re = 1200 , where the characteristics of the path, bubble shape, and vortical structures in the wake are reported.