Symmetry Breaking, Anomalous Scaling and Large-Scale Flow Generation in a Convection Cell

Original · EN

We consider a convection process in a thin loop. At Ra=Ra′cr a first transition leading to the generation of corner vortices is observed. At higher Ra a coherent large-scale flow, which persists for a very long time, sets up. The mean velocity v, mass flux, and the Nusselt number Nu in this flow scale with Ra as v ∝ m ∝ Ra⁰.⁴⁵ and Nu∝ Ra⁰.⁹, respectively. The time evolution of the coherent flow is well described by the Landau amplitude equation within a wide range of Ra-variation. The anomalous scaling of the mean velocity, found in this work, resembles the one experimentally observed in the ``hard turbulence'' regime of Benard convection. A possible relation between the two systems is discussed.