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Thermohaline interleaving induced by horizontal temperature and salinity gradients from above

Published online by Cambridge University Press:  21 September 2021

Junyi Li  and
Yantao Yang Open the ORCID record for Yantao Yang [Opens in a new window]
Junyi Li
Affiliation:
State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, PR China
Yantao Yang*
Affiliation:
State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, PR China Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing 100871, PR China
*
†Email address for correspondence: yantao.yang@pku.edu.cn
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Abstract

In this work we show that horizontal gradients of temperature and salinity with compensating effects on density can drive thermohaline intrusion in the fluid layer below. Specifically, different types of double diffusive convection generate differential vertical fluxes from the top boundary, which then sustain horizontal temperature and salinity gradients within the bulk. Interleaving layers develop in the bulk and slope downward towards the cold fresh side, which are of the diffusive type. New layers emerge near the bottom boundary and shift the existing layers upward due to the density difference induced by the divergence of the vertical fluxes through the top surface. Detailed analyses reveal that the present intrusion is consistent with those in the narrow fronts, and both layer thickness and current velocity follow the corresponding scaling laws. Such intrusion process provides an extra path to transfer heat and salinity horizontally towards the cold and fresh side, but transfer the density anomaly towards the warm and salty side. These findings extend the circumstances where thermohaline intrusions may be observed.

JFM classification

Convection: Double diffusive convection Turbulent Flows: Turbulent convection Turbulent Flows: Turbulence simulation
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 927 , 25 November 2021 , A12
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Copyright
© The Author(s), 2021. Published by Cambridge University Press

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References

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Li and Yang supplementary movie

The upward shifting of the interleaving layers for case 2. The movie shows the time evolutions of four flow quantities over the vertical mid-plane in the spanwise direction.

Download Li and Yang supplementary movie(Video)
Video 3.1 MB