Turbulent horizontal convection at high Schmidt numbers

Abstract

Horizontal convection is flow driven by a buoyancy gradient imposed along a horizontal boundary. It is a simple model to study the influence of heating, cooling, and fresh water fluxes at the ocean surface on the meridional overturning circulation [1]. In order to investigate the flow properties and energetics of horizontal convection at high Schmidt numbers Sc = ν/κ, where in the present case ν ≈ 10 6 m 2 /s is the kinematic viscosity and κ ≈ 1.64 × 10 9 m 2 /s is the diffusion coefficient of salt in water, the flow is driven by the diffusion of salt in water across reinforced permeable FIG. 1. Side view of the tank, illuminated from the left and showing the evolution of fresh fluorescein dye water released from the right. The temporal evolution of the circulation is described by the transport of the fluorescein (green/yellow) dye, driven by a solutal horizontal density gradient, creating a turbulent plume sinking on the left of the tank (a-f). The deep circulation is shown in (g) where the flow has developed and drives a deep but weakly turbulent circulation that eventually upwells on the right of the tank.

New Laboratory Experiments to Study the Large-Scale Circulation and Climate Dynamics

“…In this configuration, a horizontal surface at the lower or the upper boundary is heated differentially [3]. Some authors use salt to generate a surface buoyancy gradient [4]. In other versions, parts of the upper and lower boundaries are heated with different temperatures or the sidewalls of the tank considered are kept at different fixed temperatures.…”

Thermal boundary-layer structure in laminar horizontal convection

“…Moreover, as it was shown recently in Wang, Lohse & Shishkina (2021), HC is closely related to internally heated convection, where the thermal driving is not due to specific thermal boundary conditions but a bulk thermal source. A number of recent theoretical, experimental and numerical studies are dedicated to the transport properties and large-scale circulation in HC under various boundary conditions (Wang & Huang 2005;Sheard & King 2011;Griffiths, Hughes & Gayen 2013;Shishkina, Grossmann & Lohse 2016;Shishkina & Wagner 2016;Passaggia et al 2017a;Passaggia, Scotti & White 2017b;Shishkina 2017;Wang, Huang & Xia 2018;Ramme & Hansen 2019;Reiter & Shishkina 2020;Tsai et al 2020). However, current understanding of the thermal BL structure in HC remains rather limited.…”

“…2016; Passaggia et al. 2017 a ; Passaggia, Scotti & White 2017 b ; Shishkina 2017; Wang, Huang & Xia 2018; Ramme & Hansen 2019; Reiter & Shishkina 2020; Tsai et al. 2020).…”