Generation of turbulence through frontogenesis in sheared stratified flows
The large-scale structures in the ocean and the atmosphere are in geostrophic balance, and a conduit must be found to channel the energy to the small scales where it can be dissipated. In turbulence, this takes the form of an energy cascade, whereas a possible mechanism in a balanced flow is through...
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2018
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10706631_v30_n8_p_Sujovolsky http://hdl.handle.net/20.500.12110/paper_10706631_v30_n8_p_Sujovolsky |
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paper:paper_10706631_v30_n8_p_Sujovolsky2023-06-08T16:04:35Z Generation of turbulence through frontogenesis in sheared stratified flows Aspect ratio Turbulence Boussinesq equations Geostrophic balance Large aspect ratio Large scale structures Numerical experiments Possible mechanisms Small-scale modeling Stratified flows Shear flow The large-scale structures in the ocean and the atmosphere are in geostrophic balance, and a conduit must be found to channel the energy to the small scales where it can be dissipated. In turbulence, this takes the form of an energy cascade, whereas a possible mechanism in a balanced flow is through the formation of fronts, a common occurrence in geophysics. We show that an iconic configuration in laboratory and numerical experiments for the study of turbulence, the so-called Taylor-Green or von Kármán swirling flow, can be suitably adapted to domains with large aspect ratios, leading to the creation of an imposed large-scale vertical shear. To this effect, we use direct numerical simulations of the Boussinesq equations without net rotation and with no small-scale modeling. Various grid spacings are used, up to 20482 × 256 spatial points. The grids are always isotropic, with box aspect ratios of either 1:4 or 1:8. We find that when shear and stratification are comparable, the imposed shear layer resulting from the forcing leads to the formation of fronts and filaments which destabilize and evolve into a turbulent flow in the bulk, with a sizable amount of dissipation and mixing, following a cycle of front creation, instability, and development of turbulence. The results depend on the vertical length scales of shear and stratification. © 2018 Author(s). 2018 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10706631_v30_n8_p_Sujovolsky http://hdl.handle.net/20.500.12110/paper_10706631_v30_n8_p_Sujovolsky |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Aspect ratio Turbulence Boussinesq equations Geostrophic balance Large aspect ratio Large scale structures Numerical experiments Possible mechanisms Small-scale modeling Stratified flows Shear flow |
| spellingShingle |
Aspect ratio Turbulence Boussinesq equations Geostrophic balance Large aspect ratio Large scale structures Numerical experiments Possible mechanisms Small-scale modeling Stratified flows Shear flow Generation of turbulence through frontogenesis in sheared stratified flows |
| topic_facet |
Aspect ratio Turbulence Boussinesq equations Geostrophic balance Large aspect ratio Large scale structures Numerical experiments Possible mechanisms Small-scale modeling Stratified flows Shear flow |
| description |
The large-scale structures in the ocean and the atmosphere are in geostrophic balance, and a conduit must be found to channel the energy to the small scales where it can be dissipated. In turbulence, this takes the form of an energy cascade, whereas a possible mechanism in a balanced flow is through the formation of fronts, a common occurrence in geophysics. We show that an iconic configuration in laboratory and numerical experiments for the study of turbulence, the so-called Taylor-Green or von Kármán swirling flow, can be suitably adapted to domains with large aspect ratios, leading to the creation of an imposed large-scale vertical shear. To this effect, we use direct numerical simulations of the Boussinesq equations without net rotation and with no small-scale modeling. Various grid spacings are used, up to 20482 × 256 spatial points. The grids are always isotropic, with box aspect ratios of either 1:4 or 1:8. We find that when shear and stratification are comparable, the imposed shear layer resulting from the forcing leads to the formation of fronts and filaments which destabilize and evolve into a turbulent flow in the bulk, with a sizable amount of dissipation and mixing, following a cycle of front creation, instability, and development of turbulence. The results depend on the vertical length scales of shear and stratification. © 2018 Author(s). |
| title |
Generation of turbulence through frontogenesis in sheared stratified flows |
| title_short |
Generation of turbulence through frontogenesis in sheared stratified flows |
| title_full |
Generation of turbulence through frontogenesis in sheared stratified flows |
| title_fullStr |
Generation of turbulence through frontogenesis in sheared stratified flows |
| title_full_unstemmed |
Generation of turbulence through frontogenesis in sheared stratified flows |
| title_sort |
generation of turbulence through frontogenesis in sheared stratified flows |
| publishDate |
2018 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_10706631_v30_n8_p_Sujovolsky http://hdl.handle.net/20.500.12110/paper_10706631_v30_n8_p_Sujovolsky |
| _version_ |
1768543909061853184 |