Numerical Simulations of Two-Phase Shear Layers

This work presents high-fidelity numerical simulations of incompressible two-phase mixing layers with a focus on interfacial dynamics and turbulence. Two sets of simulations are conducted with two-dimensional (2D) and three-dimensional (3D) configurations using a conservative phase-field method. Grid refinement studies are carried out from N = 256 to N = 2048 grid points in both configurations to study convergence. Growth of momentum and volume-fraction-based thicknesses is examined, revealing initial linear behavior across all resolutions. However, interface breakup is increasingly delayed at higher resolutions in two-dimensional setup with the finest grid displaying unexpectedly similar behavior to coarser grids. This suggests that physical breakup mechanisms cannot be fully captured in 2D due to the absence of 3D instabilities. Visualizations further reveal significant resolution-dependent ligament breakup. A grid convergence study in 3D (with a significantly longer domain in the third dimension) was performed, obtaining a converged growth rate with increasing resolution.