Non-Gaussian Turbulence Field as a Dissipative Structure

Abstract

The dynamical mechanism producing non-Gaussian (intermittent) turbulence field with a large kurtosis is investigated on the basis of theoretical considerations and from the results of full numerical simulations of three-dimensional inviscid truncated system and Navier-Stokes equation. The simulations show that the nonlinearity plus the viscous dissipation in the Navier-Stokes equation maintain the large kurtosis; the intermittency can be characterized as a dissipative structure produced by a nonequilibrium and nonlinear system. On the other hand, the phase correlation producing the large kurtosis may contribute to the energy transfer. This result indicates that the intermittency and the energy transfer have a complementary relation to each other.