抄録
The Wiener-Hermite expansion with the time-dependent ideal random function is applied to the nearly Gaussian isotropic turbulence. The first two terms of the expansion are used for the numerical calculations of the initial Gaussian distributions whose energy spectra are not so different from the expected quasi-stable spectrum. The kinematic viscosity is set at 0.01. The characteristic wave number and velocity are considered to be of the order of 0.5 and 1 respectively in these initial conditions. It is shown that the variations of the shapes of the energy spectra, starting from these initial conditions, support Kolmogoroff’s quasi-stable spectrum E(k)∼k−5⁄3 in the wave number range 1<k<2.8. E(k)∼k2 in the range k∼0 and E(k)∼k−σ(4<σ<5) in the range 8<k<11, are also suggested although the inclination is not so definite as in the above range.
