Turbulence and heat transfer on a rotating, heated half soap bubble
Abstract
We use Direct Numerical Simulations to study the twodimensional flow of a rotating, half soap bubble that is heated at its equator. The heating produces buoyancy and rotation generates a Coriolis forces in the fluid. However, due to the curved surface of the bubble, the buoyancy and Coriolis forces vary with latitude on the bubble, giving rise to rich flow behavior. We first explore the singlepoint properties of the flow, including the Reynolds and Nusselt numbers, mean fields, and Reynolds stresses, all as a function of latitude. For a given Rayleigh number, we observe a nonmonotonic dependence on the Rossby number Ro, and large scale mean circulations that are strongly influenced by rotation. We then consider quantities that reveal the multiscale nature of the flow, including spectrums and spectral fluxes of kinetic and thermal energy, and enstrophy, and structure functions of velocity and temperature. The fluxes show that just a for nonbuoyant twodimensional turbulence on a flat surface, there is an upscale flux of kinetic energy at larger scales (fed by buoyancy injection of turbulent kinetic energy at smaller scales), and a downscale flux of enstrophy at smaller scales. The kinetic energy spectrum and velocity structure functions are well described by BolgianoObukhov (BO) scaling at scales where the effects of rotation are weak. The temperature structure functions do not, however, satisfy BO scaling in general, due to strong intermittency in the temperature field.
 Publication:

Journal of Fluid Mechanics
 Pub Date:
 October 2021
 DOI:
 10.1017/jfm.2021.610
 arXiv:
 arXiv:2011.09235
 Bibcode:
 2021JFM...924A..19H
 Keywords:

 Physics  Fluid Dynamics
 EPrint:
 doi:10.1017/jfm.2021.610