抄録
Using orthonormal, divergence-free wavelets, which is given by unitary trasform of complex helical waves, we analysed a homogeneous, isotropic turbulence data obtained by a direct numerical simulation. Three-dimensional wavelet analysis requires such novel representations of wavelet spectra that represents the spatial location and amplitude, so we developed the ball representation of spectrum. Ball representation of wavelet spectrum reveals that kinetic energy of turbulence transfers not only to the small scales but also to the larger scales with almost same order of amplitude, i.e., backscatter phenomena actively occurs.
