開水路流れにおける乱れの空間構造について (5)

Abstract

The one-dimensional turbulent energy spectrum is well described by the similarityobtained through the method of the dimensional analysis. Applying the same techniqueto the spatial structure of turbulence, the following similarities are obtained, that is, thelongitudinal coherency is approximated by a constant in the production subrange, -2/3power law in the inertial subrange and -2 or -6 power law in the viscous subrange, respectively, whereas the longitudinal phase-lag is the product of the wave number bythe longitudinal distance.According to this similarities, it may be concluded that the large scale turbulence is dis-continuously devided and the intermediate and small scale turbulence are continuouslytransformed to the smaller ones.The above similarities of the spatial structure of turbulence are examined by the ex-periments, where the multi-point measurements of velocities are performed by simultaneoususing of two hot-film flowmeters.