Numerical investigation of shear turbulence and melting-freezing boundary interactions

When a turbulent flow interacts with a solid-phase boundary at near-freezing temperature, the fluid may freeze or melt depending on the local temperature. The near-wall turbulent structures affect the convective heat transport patterns, leading to the formation of complex phase-boundary morphologies. The phase-boundary evolves as part of the solution and modifies the near-boundary fluid structures, generating a feedback loop. We investigate this problem by examining the interaction between shear turbulence and a melting boundary via DNS of an open channel flow at shear Reynolds number between 170 and 226. The upper part of the channel is occupied by the solid phase, while free shear conditions are applied at the bottom. Temperature is imposed on both walls. Phase change is simulated using a phase field method combined with a volume penalization immersed boundary method. A pseudo-spectral scheme is used to solve for the governing equations (Navier Stokes, Allen Cahn, and heat transport). We analyze the correlation between interface morphology, heat transfer patterns, and near-boundary flow structures, in order to better understand the interplay between these features of the flow and to highlight their collective influence on the local and global parameters of the physical system.