دورية أكاديمية
Direct and large-eddy simulations of internal tide generation at a near-critical slope
| العنوان: | Direct and large-eddy simulations of internal tide generation at a near-critical slope |
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| المؤلفون: | Gayen, Bishakhdatta, Sarkar, S |
| المصدر: | Journal of Fluid Mechanics |
| بيانات النشر: | Cambridge University Press |
| المجموعة: | Australian National University: ANU Digital Collections |
| مصطلحات موضوعية: | Keywords: A-thermal, Baroclinic, Barotropic tides, Boundary flows, Boundary-layer solution, Critical region, Dissipation rates, Free wave propagation, Higher harmonics, Inter-harmonics, Internal tide generation, Internal waves, Nonlinear process, Numerical studies, stratified turbulence |
| الوصف: | A numerical study is performed to investigate nonlinear processes during internal wave generation by the oscillation of a background barotropic tide over a sloping bottom. The focus is on the near-critical case where the slope angle is equal to the natural internal wave propagation angle and, consequently, there is a resonant wave response that leads to an intense boundary flow. The resonant wave undergoes both convective and shear instabilities that lead to turbulence with a broad range of scales over the entire slope. A thermal bore is found during upslope flow. Spectra of the baroclinic velocity, both inside the boundary layer and in the external region with free wave propagation, exhibit discrete peaks at the fundamental tidal frequency, higher harmonics of the fundamental, subharmonics and inter-harmonics in addition to a significant continuous part. The internal wave flux and its distribution between the fundamental and harmonics is obtained. Turbulence statistics in the boundary layer including turbulent kinetic energy and dissipation rate are quantified. The slope length is varied with the smaller lengths examined by direct numerical simulation (DNS) and the larger with large-eddy simulation (LES). The peak value of the near-bottom velocity increases with the length of the critical region of the topography. The scaling law that is observed to link the near-bottom peak velocity to slope length is explained by an analytical boundary-layer solution that incorporates an empirically obtained turbulent viscosity. The slope length is also found to have a strong impact on quantities such as the wave energy flux, wave energy spectra, turbulent kinetic energy, turbulent production and turbulent dissipation. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | unknown |
| تدمد: | 0022-1120 |
| العلاقة: | http://hdl.handle.net/1885/65124Test; https://openresearch-repository.anu.edu.au/bitstream/1885/65124/5/Gayern_2011_direct_large_eddy_simulations.pdf.jpgTest; https://openresearch-repository.anu.edu.au/bitstream/1885/65124/7/01_Gayen_Direct_and_large-eddy_2011.pdf.jpgTest |
| DOI: | 10.1017/jfm.2011.170 |
| الإتاحة: | https://doi.org/10.1017/jfm.2011.170Test http://hdl.handle.net/1885/65124Test https://openresearch-repository.anu.edu.au/bitstream/1885/65124/5/Gayern_2011_direct_large_eddy_simulations.pdf.jpgTest https://openresearch-repository.anu.edu.au/bitstream/1885/65124/7/01_Gayen_Direct_and_large-eddy_2011.pdf.jpgTest |
| رقم الانضمام: | edsbas.C3427585 |
| قاعدة البيانات: | BASE |
| تدمد: | 00221120 |
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| DOI: | 10.1017/jfm.2011.170 |