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DY: Fachverband Dynamik und Statistische Physik
DY 5: Convection
DY 5.8: Talk
Monday, April 1, 2019, 12:15–12:30, H3
Inclined thermal convection in liquid metals — •Lukas Zwirner and Olga Shishkina — Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen
Any tilt of a Rayleigh-Benard convection (RBC) cell against gravity changes the global flow structure inside the cell. Recent experiments by Vasil'ev et al. (2015, Tech. Phys. 60) and Frick et al. (2015, Europhys. Lett. 109) with liquid sodium (Prandtl number Pr<<1) demonstrated that the heat transport in low-Prandtl number fluids is especially sensitive to the inclination angle. Our study is based on direct numerical simulations of inclined convection in a cylindrical cell of diameter-to-height aspect ratios 1 and 1/5 and we consider Prandtl numbers down to Pr=0.0083. We demonstrate that the global flow structure like the large scale circulation is influenced by both the inclination angle and the lateral confinement of the cell. For inclined convection we observe the formation of two system-sized plume columns, a hot and a cold one, that impinge on the opposite boundary layers (Zwirner and Shishkina, 2018, J. Fluid Mech. 850). In RBC the confined cell supports the formation of multiple rolls on top of each other.
The work is supported by the German Research Foundation under the grant SH405/7 and Heisenberg fellowship SH405/4. We acknowledge the Leibniz Supercomputing Centre (LRZ) for providing computing resources on SuperMUC.