The statistical behaviour of turbulent energy dissipation

The statistical properties of the dissipation of turbulent energy were examined. One of the principal problems inherent in its study arises from the representation of the dissipation in terms of only one or two velocity gradients. The statistics of local spatial averages of epsilon were studied for the case of grid-generated turbulence using different representations for epsilon. These representations involve the longitudinal gradient of longitudinal and/or transverse velocity fluctuations. The resulting expressions are all in principle equivalent theoretical representations. The statistical behavior epsilon was compared to the lognormal model. All representation agree with the lognormal model if the domain sizes used in local averages are larger than 1.6 cm and provide equivalent statistical results.