Lagrangian statistics of heat transfer in homogeneous turbulence driven by Boussinesq convection

Pratt, J., Busse, A. and Müller, W.-C. (2020) Lagrangian statistics of heat transfer in homogeneous turbulence driven by Boussinesq convection. Fluids, 5(3), 127. (doi: 10.3390/fluids5030127)

Abstract

The movement of heat in a convecting system is typically described by the nondimensional Nusselt number, which involves an average over both space and time. In direct numerical simulations of turbulent flows, there is considerable variation in the contributions to the Nusselt number, both because of local spatial variations due to plumes and because of intermittency in time. We develop a statistical approach to more completely describe the structure of heat transfer, using an exit-distance extracted from Lagrangian tracer particles, which we call the Lagrangian heat structure. In a comparison between simulations of homogeneous turbulence driven by Boussinesq convection, the Lagrangian heat structure reveals significant non-Gaussian character, as well as a clear trend with Prandtl number and Rayleigh number. This has encouraging implications for simulations performed with the goal of understanding turbulent convection in natural settings such as Earth’s atmosphere and oceans, as well as planetary and stellar dynamos.

• Item Type: Articles
• Additional Information: This material is based upon work supported by the US National Science Foundation PHY-1907876. It is also supported by the Thomas Jefferson Fund project entitled “Statistics of turbulent convection.” ThisworkusedtheARCHERUKNationalSupercomputingService(http://www.archer.ac. uk) as part of the UK Turbulence Consortium. This work has been supported by the Engineering and Physical Sciences Research Council Grants No. EP/L000261/1. Additional calculations were performed on the Konrad and Gottfried computer systems of the Norddeutsche Verbund zur Förderung des Hoch- und Höchstleistungsrechnens (HLRN) by the project bep00051 “Lagrangian studies of incompressible turbulence in plasmas”. Calculations were performed on the Cluster-I of the Technical University of Berlin, and the University of Exeter Supercomputer, a DiRAC Facility jointly funded by STFC, the Large Facilities Capital Fund of BIS and the University of Exeter.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Busse, Professor Angela

Creator Roles

Busse, A.: Software, Validation, Formal analysis, Investigation, Resources, Writing – original draft, Writing – review and editing

• Authors: Pratt, J., Busse, A., and Müller, W.-C.
• College/School: College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity
• Journal Name: Fluids
• Publisher: MDPI
• ISSN: 2311-5521
• ISSN (Online): 2311-5521
• Published Online: 03 August 2020
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Fluids 5(3): 127
• Publisher Policy: Reproduced under a Creative Commons License