Mixing and Interpenetration in a Three-Dimensional Buoyancy-Driven Flow of Two Immiscible Liquids: A GPU Based LBM Approach

Y The Buoyancy-driven flow of two immiscible liquids having varying density and viscosity is studied in a three-dimensional inclined confined channel. Initially , the heavier/lighter liquids occupy the upper/lower parts of the channel , respectively , which is an unstable configuration. The numerical simulations are performed using a multiphase lattice Boltzmann method (LBM) that is further implemented on the graphics processing unit (GPU). The three-dimensional flow dynamics and the associated physics are studied based on various parameters such as viscosity ratios (m) , Atwood numbers (At) and Reynolds numbers (Re). The results were presented in the form of iso-surface/contour plots , average density profiles , and lengths of interpenetration. It is observed that larger interpenetration occurs with iso-viscous liquids having higher density gradients (higher At). The Reynolds number had a non-monotonic effect on the axial lengths of interpenetration (Lp*); Lp* increases till Re = 500 and then decreases for Re = 1000. At larger Re, due to the development of Kelvin-Helmholtz instabilities higher transverse interpenetration is observed.

Automated summary

The buoyancy-driven flow of two immiscible liquids with varying density and viscosity in a three-dimensional inclined confined channel was studied. It was found that iso-viscous liquids with higher At values exhibit larger interpenetration.