一様等方性乱流の減衰特性

概要

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Decay process of homogeneous turbulence excited by a turbulence generator was experimentally investigated. The turbulence field initially had apparent anisotropy due to the turbulence generator. It decayed downstream into quasi-isotropic turbulence through two stages characterized by the relationship between turbulence energy q^2 and invariant II of an anisotropic tensor. The return to isotropy proceeded in the first stage and the viscous dissipation dominated in the second stage where the turbulence still maintained weak anisotropy similar to conventional grid turbulence. A new method of determining the virtual origin was proposed and a power law was derived from the equation of turbulence energy employing Rotta's model in order to take the return to isotropy into account. Almost the same decay rate was obtained in both the first and second stages.
社団法人日本機械学会の論文
1996-02-25