Entropy and energy spectra in low Prandtl number convection with rotation
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Author: Hirdesh K. Pharasi, Krishna Kumar, Jayanta K. Bhattacharjee
Added by: arkiver
Added Date: 2018-06-30
Subjects: Fluid Dynamics, Physics
Publishers: arXiv.org
PDF Count: 1
Total Size: 1.38 MB
PDF Size: 1.36 MB
Extensions: pdf, torrent
Contributor: Internet Archive
License: Unknown License
Downloads: 15
Views: 65
Total Files: 6
Media Type: texts
Total Files: 2
Description
We present results for entropy and kinetic energy spectra computed from direct numerical simulations for low-Prandtl-number ($Pr < 1$) turbulent flow in Rayleigh-B\'{e}nard convection with uniform rotation about a vertical axis. The simulations are performed in a three-dimensional periodic box for a range of Taylor number ($ 0 \leq Ta \leq 10^8$) and reduced Rayleigh number $r = Ra/Ra_{\circ} (Ta, Pr)$ ($1.0 \times 10^2 \le r \le 5.0 \times 10^3$). The Rossby number $Ro$ varies in the range $1.34 \le Ro \le 73$. The entropy spectrum $E_{\theta}(k)$ shows bi-splitting into two branches for lower values of wave number $k$. The entropy in the lower branch scales with $k$ as $k^{-1.4\pm 0.1}$ for $r > 10^3$ for the rotation rates considered here. The entropy in the upper branch also shows scaling behavior with $k$, but the scaling exponent decreases with increasing $Ta$ for all $r$. The energy spectrum $E_v(k)$ is also found to scale with the wave number $k$ as $k^{-1.4\pm 0.1}$ for $r > 10^3$. The scaling exponent for the energy spectrum and the lower branch of the entropy spectrum vary between $-1.7$ to $-2.4$ for lower values of $r$ ($< 10^3$). We also provide some simple arguments based on the variation of the Kolmogorov picture to support the results of simulations.
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