Articles | Volume 13, issue 2
Nonlin. Processes Geophys., 13, 205–222, 2006
https://doi.org/10.5194/npg-13-205-2006

Special issue: Coherent structures and turbulence in geophysical media

Nonlin. Processes Geophys., 13, 205–222, 2006
https://doi.org/10.5194/npg-13-205-2006

  21 Jun 2006

21 Jun 2006

Numerical simulation of helical-vortex effects in Rayleigh-Bénard convection

G. V. Levina and I. A. Burylov G. V. Levina and I. A. Burylov
  • Institute for Continuous Media Mechanics, UB RAS, Perm, Russia

Abstract. A numerical approach is substantiated for searching for the large-scale alpha-like instability in thermoconvective turbulence. The main idea of the search strategy is the application of a forcing function which can have a physical interpretation. The forcing simulates the influence of small-scale helical turbulence generated in a rotating fluid with internal heat sources and is applied to naturally induced fully developed convective flows. The strategy is tested using the Rayleigh-Bénard convection in an extended horizontal layer of incompressible fluid heated from below. The most important finding is an enlargement of the typical horizontal scale of the forming helical convective structures accompanied by a cells merging, an essential increase in the kinetic energy of flows and intensification of heat transfer. The results of modeling allow explaining how the helical feedback can work providing the non-zero mean helicity generation and the mutual intensification of horizontal and vertical circulation, and demonstrate how the energy of the additional helical source can be effectively converted into the energy of intensive large-scale vortex flow.