Turbulent transition and maintenance of turbulence; implication to heat transfer augmentation
| Autor: | J. Kapat, B. B. Mikic, Lj.B. Vujisic |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Turbulence K-epsilon turbulence model Mechanical Engineering Reynolds number Thermodynamics Context (language use) Mechanics Heat transfer coefficient Vorticity Condensed Matter Physics Physics::Fluid Dynamics symbols.namesake Bounded function Heat transfer symbols |
| Zdroj: | International Journal of Heat and Mass Transfer. 37:425-431 |
| ISSN: | 0017-9310 |
| DOI: | 10.1016/0017-9310(94)90042-6 |
| Popis: | In this communication we present formulation of a criterion for (turbulent) transition for wall bounded flows. In addition, we discuss the implication of the findings to heat transfer augmentation. The presentation has three parts. First, we argue that transition to turbulence should be interpreted solely in the context of the system's capacity to maintain turbulent motions. Second, we propose a model that links maintenance of turbulence to the intermittent transfer of vorticity from the wall region (the demarcation of transition follows directly from the model: it is simply a limiting case of the conditions for maintenance). Third, we apply the findings to estimate heat transfer in the transition region. Experimental results show a good agreement with the proposed criterion; they show a strong cause-effect coherency between vorticity production and the system capacity to maintain turbulence (a correspondence implied by the proposed model). It was also found that the heat transfer coefficient in the transition region is significantly increased when the transition Reynolds number is lowered through deployment of suitable augmentation schemes. |
| Databáze: | OpenAIRE |
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