| 日時： |
2006年09月08日（金） 14:00〜 |
| 場所： |
京都大学大学院 工学研究科 航空宇宙工学専攻 2階 会議室 |
| 講演者： |
Dr. Robert Rubinstein (Computational AeroSciences Branch, NASA Langley Research Center, Hampton, VA, USA) |
| 講演題目： |
Kinetic theory and turbulence modeling |
| 講演要旨： |
The oldest heuristic in turbulence modeling connects turbulent transport to kinetic theory through an analogy between molecular fluctuations and hydrodynamic fluctuations. We explore another analogy of this type. Under appropriate hypotheses, the Chapman-Enskog expansion justifies approximating the evolution of the distribution function in six-dimensional phase space by a system of partial differential equations in three-dimensional configuration space, namely, the Navier-Stokes equations. A similar method is applied to extract a closed system of equations governing scalar descriptors of the turbulence energy spectrum from a spectral closure model by replacing the local Maxwellian of kinetic theory by a local Kolmogorov spectrum characterized by two slowly varying functions of time. Similarities and differences between the Navier-Stokes equations and the resulting `two-equation' turbulence model will be discussed. |
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