プルーム拡散場の等濃度点集合のフラクタル性と球による流れ場の変形の影響

概要

論文の詳細を見る
This paper gives a detailed investigation of the fractal feature of sets of isoconcentration points taken from data on an axisymmetric point source plume which is evolved in grid-generated turbulence and distorted by a sphere. The following points are clarified in this paper : (1) The fractal dimensions of sets of isoconcentration points, D_<f1>, are valued at approximately 0.3, and are likely to be independent of the threshold level of a wide range of concentration : (2) Although there is no clear range of the -5/3 power law in the spectra of the turbulence and the concentration fluctuation, sets of isoconcentration points appear to be fractal-like, and the fractal dimension is close to the value of 0.36±0.05, found in high Reynolds number flows : (3) The distortion of flow due to a sphere has almost no effect on the magnitude of the fractal dimension of a set of isoconcentration points, but merely gives rise to the change of the boxsize range within which the fractality holds.
1993-09-25