Similarities between 2D and 3D convection for large Prandtl number etc15 Tracking Number 290Presentation: Session: Geophysical and astrophysical turbulence 2 Room: Room C Session start: 15:00 Thu 27 Aug 2015 Anando Chatterjee anandogc@iitk.ac.in Affifliation: IIT Kanpur, Kanpur, India Ambrish Pandey pambrish@iitk.ac.in Affifliation: IIT Kanpur, Kanpur, India Mahendra Verma mkv@iitk.ac.in Affifliation: IIT Kanpur, Kanpur, India Biplab Dutta bdutta@iitk.ac.in Affifliation: IIT Kanpur, Kanpur, India Topics: - Geophysical and astrophysical turbulence, - Thermally driven turbulence Abstract: Using direct numerical simulations of Rayleigh-B\'enard convection (RBC), we perform a comparative study of the spectra and fluxes of energy and entropy for large and infinite Prandtl numbers in two (2D) and three (3D) dimensions. We observe close similarities between the 2D and 3D RBC, in particular the kinetic energy spectrum $E_u(k) \sim k^{-13/3}$, and the entropy spectrum exhibits a dual branch with a dominant $k^{-2}$ spectrum. We showed that the dominant Fourier modes in the 2D and 3D flows are very close. |