Abstract
We present three-dimensional direct numerical simulations of internal waves excited by turbulent convection in a self-consistent, Boussinesq and Cartesian model of mixed convective and stably stratified fluids. We demonstrate that in the limit of large Rayleigh number and large stratification (Brunt-Väisälä frequencies , where is the convective frequency), simulations are in good agreement with a theory that assumes waves are generated by Reynolds stresses due to eddies in the turbulent region as described in Lecoanet & Quataert (Mon. Not. R. Astron. Soc., vol. 430 (3), 2013, pp. 2363-2376). Specifically, we demonstrate that the wave energy flux spectrum scales like for weakly damped waves (with and the waves' horizontal wavenumbers and frequencies, respectively), and that the total wave energy flux decays with , the distance from the convective region, like .
| Original language | English (US) |
|---|---|
| Pages (from-to) | R3 |
| Journal | Journal of fluid Mechanics |
| Volume | 854 |
| DOIs | |
| State | Published - Nov 10 2018 |
Funding
The authors acknowledge funding by the European Research Council under the European Union’s Horizon 2020 research and innovation program through Grant no. 681835-FLUDYCO-ERC-2015-CoG. D.L. is supported by a PCTS fellowship and a Lyman Spitzer Jr fellowship. Computations were conducted with support by the HPC resources of GENCI-IDRIS (Grant no. A0020407543 and A0040407543) and by the NASA High End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center on Pleiades with allocations GID s1647 and s1439. We thank two anonymous referees and N. Grisouard for critically reading our manuscript and suggesting substantial improvements.
Keywords
- geophysical and geological flows
- internal waves
- turbulent convection
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering