Wed March 23rd 2016
16:00 – 17:00
ZH286 		Seminar What Confined and Rotating Turbulent Rayleigh-Bénard Convection Have in Common?
Ke-Qing Xia

Details:

In the first part of the talk, using thermal plumes as an example, I will show how manipulation of coherent structures can result in enhanced turbulent transport and the emergence of coherent structure condensations. For the specific case of geometrical confinement in turbulent Rayleigh-Bénard convection, the result is
the formation of highly coherent system-sized plumes and the emergence of a
new regime of convective thermal turbulence characterized by universal
temperature profiles and significantly enhanced heat transfer. It is also found
that the universality of the temperature profiles and heat transport originate from the geometrical properties of the coherent structures, i.e., the thermal plumes.
In the second part of the talk, I will present a preliminary study of the transition from highly confined to non-confined regimes. The results reveal similarities for the global transport behavior with the transition from geostrophic to nonrotating behavior in rotating Rayleigh-Bénard convection. In particular, we identify a parameter that can be used to characterize the transition from the highly confined to non-confined regimes. It is further found that this parameter can be used to well collapse the observed Nusselt and Reynolds numbers for different strengths of confinement.
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