Shear capacity as prognostic of nocturnal boundary layer regimes
| Autor: | Hooijdonk, I., Donda, J., Bosveld, F., Arnold Moene, Clercx, H., Wiel, B. |
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| Přispěvatelé: | Fluids and Flows, Transport in Turbulent Flows (Clercx) |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | ISSUE=15;TITLE=15th European Turbulence Conference, ETC 2015 Scopus-Elsevier |
| Popis: | In some nights, the near-surface temperature can drop dramatically and turbulence in the stably stratified boundary layer becomes very weak, such that the lfow reaches a (quasi-) laminar state. In other cases, however, the atmosphere remains in a turbulent state and temperatures stay relatively high. Recently, the appearance of two distinct boundary layer regimes was explained by a new theoretical framework. This theory builds on the fact that the turbulent heat flux in stably stratified flow is limited to a maximum for given wind shear. This introduces a characteristic flux-based velocity scale, which can be used to predict the regimes. This hypothesis is consistent with field observations and numerical results. Also, the hypothesis is generalised to a dimensionless framework. |
| Databáze: | OpenAIRE |
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