In this paper we report numerical and experimental results on the scaling properties of the velocity turbulent fields in several flows. The limits of a new form of scaling, named Extended Self-Similarity (ESS), are discussed. We show that, when a mean shear is absent, the self-scaling exponents are universal and they do not depend on the specific flow (3D homogeneous turbulence, thermal convection, MHD). In contrast, ESS is not observed when a strong shear is present. We propose a generalized version of self-scaling which extends down to the smallest resolvable scales even in cases where ESS is not present. This new scaling is checked in several laboratory and numerical experiments. A possible theoretical interpretation is also proposed. A synthetic turbulent signal having most of the properties of a real one has been generated. Copyright © 1996 Elsevier Science B.V. All rights reserved.

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