Numerical and experimental analysis of the double-diffusive convection in a linearly stratified medium

Abstract

Introduction: In this paper, we numerically and experimentally studied the onset and the mechanisms of spatiotemporal evolution of the double convective diffusion in a saline medium linearly stratified and heated from below at a constant temperature. Methodology: The numerical simulations were based on the solution of the Navier–Stokes,energy, and concentration equations in stream-vorticity formulation. The numerical method used is the Hermitian compact one. In the experimental studies, a transparent cavity with free surface was filled with linearly stratified solution. The solution was heated from below at a constant temperature. The convective motions were visualized using shadowgraph to obtain more information on density exchange through the interfaces. Furthermore, particle image velocimetry (PIV) is used to measure the time evolution of the velocity field. Results: Flow visualizations by Shadowgraph and PIV allowed the comparison between experimental and numerical results. Conclusion: It was found that a multicellular flow oscillating in space and time mechanisms was observed in both experimental and numerical studies.