July 1, 2019 Presentation Open Access

Schindler, Felix; Zürner, Till; Vogt, Tobias; Eckert, Sven; Schumacher, Jörg

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{
  "url": "https://rodare.hzdr.de/record/228", 
  "inLanguage": {
    "@type": "Language", 
    "name": "English", 
    "alternateName": "eng"
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  "@context": "https://schema.org/", 
  "sameAs": [
    "https://www.hzdr.de/publications/Publ-30439"
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  "datePublished": "2019-07-01", 
  "creator": [
    {
      "@type": "Person", 
      "name": "Schindler, Felix", 
      "affiliation": "Helmholtz-Zentrum Dresden-Rossendorf"
    }, 
    {
      "@type": "Person", 
      "name": "Z\u00fcrner, Till", 
      "affiliation": "Technische Universit\u00e4t Ilmenau"
    }, 
    {
      "@type": "Person", 
      "name": "Vogt, Tobias", 
      "@id": "https://orcid.org/0000-0002-0022-5758", 
      "affiliation": "Helmholtz-Zentrum Dresden-Rossendorf"
    }, 
    {
      "@type": "Person", 
      "name": "Eckert, Sven", 
      "@id": "https://orcid.org/0000-0003-1639-5417", 
      "affiliation": "Helmholtz-Zentrum Dresden-Rossendorf"
    }, 
    {
      "@type": "Person", 
      "name": "Schumacher, J\u00f6rg", 
      "affiliation": "Technische Universit\u00e4t Ilmenau"
    }
  ], 
  "description": "<p>Lecture (Conference)</p>\n\n<p>11th PAMIR International Conference- Fundamental and Applied MHD July 1-5, 2019, Reims, EVEM France</p>\n\n<p>We are investigating turbulent Rayleigh-B&eacute;nard convection in liquid metal under the<br>\ninfluence of a vertical magnetic field. Utilizing a combination of thermocouple (TC) and<br>\nultrasound-Doppler-velocimetry (UDV) measurements gives us the possibility to directly<br>\ndetermine the temperature and velocity field, respectively. Further this gives us the<br>\npossibility to observe changes in the large-scale flow structure.<br>\nBy applying magnetic fields to the liquid metal convection, we quantified changes of heat<br>\nand momentum transport in the liquid metal alloy GaInSn. The experimental results of our<br>\nsetup agree well with theory findings and direct numerical simulations of the dynamics in<br>\nour convection cell. The requirement of large computing power at these parameters makes<br>\nit hard to simulate long-term dynamics with time scales from minutes to several hours. Thus<br>\nto investigate slow developing dynamics like sloshing, rotation, or deformation of the large-<br>\nscale flow structure model experiments are indispensable.<br>\nWe demonstrate the suppression of the convective flow by a vertical magnetic field in a<br>\ncylindrical cell of aspect ratio 1. In this setup Rayleigh numbers up to 6&middot;107 are<br>\ninvestigated. The flow structure at low Hartmann numbers is a single roll large scale<br>\ncirculation (LSC). Increasing the Hartmann number leads to a transition from the single-roll<br>\nLSC into a cell structure. An even stronger magnetic field supresses the flow in the center<br>\nof the cell completely and expels the flow to the side walls.<br>\nEven above the critical Hartmann numbers corresponding to the Chandrasekhar limit for<br>\nthe onset of magnetoconvection in a fluid layer without lateral boundaries we still observe<br>\nremarkable flows near the side walls. The destabilising effect of the non-conducting side<br>\nwalls was predicted by theory and simulations, and is here for the first time experimentally<br>\nconfirmed.</p>\n\n<p>&nbsp;</p>", 
  "license": "https://creativecommons.org/licenses/by/4.0/legalcode", 
  "@id": "https://doi.org/10.14278/rodare.228", 
  "name": "Low Prandtl Number Rayleigh-B\u00e9nard Convection in a Vertical Magnetic Field", 
  "@type": "PresentationDigitalDocument", 
  "version": "1.0", 
  "identifier": "https://doi.org/10.14278/rodare.228", 
  "keywords": [
    "Rayleigh-B\u00e9nard-Convection", 
    "Magnetohydrodynamic", 
    "low Prandtl Number", 
    "liquid metal", 
    "Ultrasound velocimetry"
  ]
}