A Unified Shell model for Buoyancy-Driven Turbulence etc15 Tracking Number 118Presentation: Session: Atmospheric turbulence 1 Room: Room C Session start: 10:30 Tue 25 Aug 2015 Abhishek Kumar abhkr@iitk.ac.in Affifliation: Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India Mahendra K. Verma mkv@iitk.ac.in Affifliation: Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016, India Topics: - Atmospheric turbulence, - Geophysical and astrophysical turbulence Abstract: We construct a unified shell model for stably stratified and convective turbulence. Shell model simulation of stably stratified flow in turbulent regime exhibit Bolgiano-Obukhbov (BO) scaling in which the kinetic energy spectrum varies as $k^{-11/5}$. However, simulation of convective turbulence shows Kolmogorov's spectrum. These results are consistent with the direct numerical simulations of Kumar {\em et al.} [Phys. Rev. E {\bf 90}, 023016 (2014)]. We also observe a dual scaling ($k^{-11/5}$ and $k^{-5/3}$) for a limited range of parameters in stably stratified flow. |