Clercx, H.J.H.

Geurts, B.J.

Kunnen, R.P.J.

English

Kunnen, RPJ Rudie

Clercx, HJH Herman

Geurts, BJ Bernard

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Heat transfer in turbulent rotating convection

Geurts, Bernardus J.

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University of Twente Research Information

Heat Transfer in Turbulent Rotating ConvectionR. P. J. Kunnen∗, H. J. H. Clercx∗, and B. J. Geurts∗†Rayleigh-Bénard convection is a classical problem in which a fluid layer enclosedbetween two parallel horizontal walls is heated from below. In a rotating frame ofreference the dynamics can change considerably through the fundamental involvementof a combination of buoyancy and Coriolis forces. The rotating Rayleigh-Bénard(RRB) setting is important for many applications, e.g., in engineering and climatemodelling.The dynamics of RRB convection can be characterised by three dimensionlessparameters. The Rayleigh number Ra characterises buoyancy, the Taylor number Tais associated with rotation, and the Prandtl number σ is a fluid property. Our aimis to gain a better understanding of the transport of heat across the layer that isdescribed by the Nusselt number Nu, which is a function of Ra, Ta, and σ.Direct numerical simulation (DNS) is used to calculate Nu at systematically var-ied Ta. The DNS code solves the incompressible Navier-Stokes equations in a rotatingframe of reference, coupled to the heat equation within the Boussinesq approxima-tion. Periodic boundary conditions are adopted in the horizontal directions and thevertical boundaries are treated as isothermal, no-slip walls.The cyclonic thermal plumes that erupt from the thermal boundary layers are thedominant structures in turbulent rotating convection, as shown in figure 1(a). The Tadependence of Nu is depicted in figure 1(b). At moderate Ta Nu increases, associatedwith Ekman pumping. At higher Ta a dominant geostrophic inhibition of vertical(convective) motion arises. This figure is for Ra = 2.5 × 106 and σ = 1.The velocity and temperature averages from this DNS will be compared to mea-surements in a water-filled cylindrical convection cell. Detailed velocity and temper-ature data will be obtained using stereoscopic particle image velocimetry and laserinduced fluorescence, respectively.∗Department of Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven,The Netherlands†Department of Applied Mechanics, University of Twente, P.O. Box 217, 7500 AE Enschede, TheNetherlands1051061071081010.51111.5TaNu(b)Figure 1: (a) Cyclonic thermal plumes as observed in a temperature isosurface plot.(b) Nu as a function of Ta. The line on the vertical axis indicates Nu at Ta = 0,crosses and circles are Nu calculated at top and bottom walls, respectively.

Heat transfer in turbulent rotating convection

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Repository TU/e

NARCIS

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Pure OAI Repository

University of Twente Research Information

NARCIS