Intermittency of turbulence in natural waters: patchiness in the thermocline of a lake under low winds and small-scale intermittency in the bottom boundary layer of a tidal flow
Turbulence intermittency influences so many processes in natural waters on a wide range of scales. This work analyzes intermittency, both internal and external, by considering two cases: the thermocline of a small lake under low winds and the bottom boundary layer of a tidal flow. External intermitt...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/320432 |
| Acceso en línea: | http://hdl.handle.net/10803/320432 |
| Access Level: | acceso abierto |
| Palabra clave: | Turbulencia Turbulence Capa límit Boundary layer Capa límite Aigua Natural water Agua Llacs Lakes Lagos Estany de Banyoles Lake Banyoles Lago Banyoles Small-scale intermittency Intermitencia a petita escala Intermitencia a pequeña escala 531/534 |
| Sumario: | Turbulence intermittency influences so many processes in natural waters on a wide range of scales. This work analyzes intermittency, both internal and external, by considering two cases: the thermocline of a small lake under low winds and the bottom boundary layer of a tidal flow. External intermittency in Lake Banyoles is studied based on patches. Variability of their sizes and turbulent scales is described using probability models, which are consistent with marine turbulence results. Dynamics of mixing depends on the phase of the dominant internal seiche. Episodic and powerful wind gusts generate large patches in the lake's interior. Internal intermittency is analyzed based the analysis of tidal flow data. Scaling exponents of structure functions and moments of the dissipation rate fit to multifractal model. For energetic episodes intermittency parameters approach the values expected for fully developed turbulence. They increase with decreasing of Reynolds numbers, which is associated with underdeveloped turbulence. |
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