Parameter Variability in Viscous Convection

For the optimal design of cooling and heating devices, the properties of the included fluids are crucial. The temperature dependence of viscosity deserves attention, as changes can be one order of magnitude or more. Here we examine the influence on convective motions by simulating a heating and cool...

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Main Author: Ekkehard Holzbecher
Format: Article
Language:English
Published: MDPI AG 2021-10-01
Series:Fluids
Subjects:
Online Access:https://www.mdpi.com/2311-5521/6/11/376
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author Ekkehard Holzbecher
author_facet Ekkehard Holzbecher
author_sort Ekkehard Holzbecher
collection DOAJ
description For the optimal design of cooling and heating devices, the properties of the included fluids are crucial. The temperature dependence of viscosity deserves attention, as changes can be one order of magnitude or more. Here we examine the influence on convective motions by simulating a heating and cooling experiment with a vertical cylinder by finite element computational fluid dynamics (CFD) models. Such an experimental setup in which flow patterns are determined by transient viscous convection has not been simulated before. Evaluating the general behavior of the experiment in 2D, we find a dynamic phase after and before phases with moderate changes. Flow patterns in the dynamic phase change significantly with the temperature range of the experiment. We compare the outcome of the numerical models with results from laboratory experiments, finding major discrepancies concerning the flow patterns in the dynamic phase. 3D modeling shows weaker dynamics but does not show good timing with the experiment. The study depicts the importance of parameter dependencies for convective motions and demonstrates the capabilities and limitations of models to reproduce details of viscous convection.
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spelling doaj.art-7ca14d931f8d462283462d9efa0d967f2023-11-22T23:17:17ZengMDPI AGFluids2311-55212021-10-0161137610.3390/fluids6110376Parameter Variability in Viscous ConvectionEkkehard Holzbecher0Department of Applied Geosciences, German University of Technology in Oman (GUtech), Halban 1816, OmanFor the optimal design of cooling and heating devices, the properties of the included fluids are crucial. The temperature dependence of viscosity deserves attention, as changes can be one order of magnitude or more. Here we examine the influence on convective motions by simulating a heating and cooling experiment with a vertical cylinder by finite element computational fluid dynamics (CFD) models. Such an experimental setup in which flow patterns are determined by transient viscous convection has not been simulated before. Evaluating the general behavior of the experiment in 2D, we find a dynamic phase after and before phases with moderate changes. Flow patterns in the dynamic phase change significantly with the temperature range of the experiment. We compare the outcome of the numerical models with results from laboratory experiments, finding major discrepancies concerning the flow patterns in the dynamic phase. 3D modeling shows weaker dynamics but does not show good timing with the experiment. The study depicts the importance of parameter dependencies for convective motions and demonstrates the capabilities and limitations of models to reproduce details of viscous convection.https://www.mdpi.com/2311-5521/6/11/376thermal convectiondensity-driven flowparameter dependencyCFD
spellingShingle Ekkehard Holzbecher
Parameter Variability in Viscous Convection
Fluids
thermal convection
density-driven flow
parameter dependency
CFD
title Parameter Variability in Viscous Convection
title_full Parameter Variability in Viscous Convection
title_fullStr Parameter Variability in Viscous Convection
title_full_unstemmed Parameter Variability in Viscous Convection
title_short Parameter Variability in Viscous Convection
title_sort parameter variability in viscous convection
topic thermal convection
density-driven flow
parameter dependency
CFD
url https://www.mdpi.com/2311-5521/6/11/376
work_keys_str_mv AT ekkehardholzbecher parametervariabilityinviscousconvection