NUMERICAL STUDY OF GRANULAR TURBULENCE AND THE APPEARANCE OF THE K(-5) (3) ENERGY-SPECTRUM WITHOUT FLOW/

A vibrated bed of powder, modeled by a vessel filled with monodisperse glass beads and shaken by a loud speaker, is investigated numerically with the distinct element method of molecular dynamics. When the bed is shaken vigourously, the displacement vectors of powder particles ha ve a power spectrum that depends upon the wavenumber k as k-5/3. This dependence originates in the balance of the injected and dissipative e nergy, analogous to Kolmogorov's proposal to explain the k-5/3 energy spectrum observed in the fluid turbulence. Furthermore, the same spect rum still appears even without flow in the powder. Thus Kolmogorov's a rgument appears to be more universal than believed before.