Abstract
Modelling of large-scale natural (thermally-generated) turbulent flows (such as the turbulent convection in Earth’s atmosphere, oceans, or Sun) is approached in laboratory experiments in the simplified model system called the Rayleigh-Bénard convection (RBC). We present preliminary measurements of vertical temperature profiles in the cell with the height of 4:7 m, 7:15m in diameter, obtained at the Barrel of Ilmenau (BOI), the worldwide largest experimental setup to study highly turbulent RBC, newly equipped with the Luna ODiSI-B optical fibre system. In our configuration, the system permits to measure the temperature with a high spatial resolution of 5mm along a very thin glass optical fibre with the length of 5m and seems to be perfectly suited for measurement of time series of instantaneous vertical temperature profiles. The system was supplemented with the two Pt100 vertically movable probes specially designed by us for reference temperature profiles measurements.
Highlights
Natural thermally-generated turbulent flows play a vital role in heat transfers in nature, be it the circulation in the atmosphere or the oceans, the flows under the surface of stars or in diverse branches of industry
(3.1 - 3.3) we present example test measurements obtained at two Rayleigh numbers (Ra) numbers
3.1 Temperature profiles measured by Pt100 probes
Summary
Natural thermally-generated turbulent flows play a vital role in heat transfers in nature, be it the circulation in the atmosphere or the oceans, the flows under the surface of stars or in diverse branches of industry. The RayleighBénard convection (RBC) is a simplified physical model serving for fundamental studies of thermally-generated flows occurring in an Oberbeck-Boussinesq (OB) fluid layer in gravitational field confined between two horizontal, laterally infinite and perfectly conducting plates heated from below and cooled from above [1]. The temperature variation of density ρ is supposed to be less than a few percent Breaking these conditions leads to Non-Oberbeck-Boussinesq (NOB) effects. The current work aims to extend our knowledge about NOB effects in RBC via measurement of vertical temperature profiles in the cell of Γ ∼ 1 for varying Ra numbers in the range of 1010 to 1012. In this paper we report the first experiment verifying capabilities of Luna ODISI-B for measurement of temperature profiles in RBC systems
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
