Direct Numerical Simulation of Turbulent Thermal Plume in Stably Stratified Ambient: Formulation, Numerical Methodology, Reverse Transition, Relaminarization, and Turbulent Enhancement
| Autor: | Keigo Nakai, Katsuhisa Noto |
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| Rok vydání: | 2008 |
| Předmět: |
Physics
Numerical Analysis Buoyancy Turbulence Direct numerical simulation Stratification (water) Laminar flow Rayleigh number Mechanics engineering.material Condensed Matter Physics Computer Science Applications Plume Physics::Fluid Dynamics Classical mechanics Mechanics of Materials Modeling and Simulation Thermal engineering |
| Zdroj: | Numerical Heat Transfer, Part B: Fundamentals. 53:313-357 |
| ISSN: | 1521-0626 1040-7790 |
| DOI: | 10.1080/10407790701849618 |
| Popis: | For the turbulent thermal plume of air developing in stably stratified air above a square heated plate on a horizontal solid surface with infinite area, the formulation and numerical methodology for direct numerical simulation (DNS) are developed, the DNS data at the Rayleigh number Ra = 1 × 107 are obtained by DNS computation, and the reverse transition, relaminarization, and turbulence enhancement are elucidated by the present DNS. Main conclusions are as follows. The governing equation system for DNS of the turbulent plume in stratified ambient is 3-D and time-dependent with buoyancy and varying density and properties and without assumption of turbulent, transitional, or laminar state, and is applicable to any thermal conditions of heated plate and any stratification degree. In the present DNS, the turbulent behavior, i.e., the high-frequency motion, the viscous dissipation, etc. can be reasonably considered, but the viscous dissipation heat is omitted because it is extremely small in the thermal plume... |
| Databáze: | OpenAIRE |
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