Convection in a mushy layer along a vertical heated wall

• Published in: Journal of Fluid Mechanics
• Main Authors: Boury, S., Meyer, C.R., Vasil, G.M., Wells, A.J.
• Other Authors: Matière et Systèmes Complexes (MSC), Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), NSF OCE-1829864 / WHOI GFD Summer School
• Format: Article in Journal/Newspaper
• Language: English
• Published: CCSD 2021
• Subjects: porous media; convection in porous media; buoyant boundary layers; [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph]; Sea ice
• Online Access: https://hal.science/hal-04907462; https://hal.science/hal-04907462v1/document; https://hal.science/hal-04907462v1/file/14_Boury_JFM_2021_Convection.pdf; https://doi.org/10.1017/jfm.2021.742

International audience Motivated by the mushy zones of sea ice, volcanoes and icy moons of the outer solar system, we perform a theoretical and numerical study of boundary-layer convection along a vertical heated wall in a bounded ideal mushy region. The mush is comprised of a porous and reactive binary alloy with a mixture of saline liquid in a solid matrix, and is studied in the near-eutectic approximation. Here, we demonstrate the existence of four regions and study their behaviour asymptotically. Starting from the bottom of the wall, the four regions are (i) an isotropic corner region; (ii) a buoyancy dominated vertical boundary layer; (iii) an isotropic connection region; and (iv) a horizontal boundary layer at the top boundary with strong gradients of pressure and buoyancy. Scalings from numerical simulations are consistent with the theoretical predictions. Close to the heated wall, the convection in the mushy layer is similar to a rising buoyant plume abruptly stopped at the top, leading to increased pressure and temperature in the upper region, whose impact is discussed as an efficient melting mechanism.