Experimental evidence for anomalous scale dependent cascading process in turbulent velocity statistics

We use a wavelet-based deconvolution method to extract some multiplicative cascading process from experimental turbulent velocity signals. We show tha t at the highest accessible Reynolds numbers, the experimental data do not allow us to discriminate between various phenomenological cascade models re cently proposed to account for intermittency and their log-normal approxima tions. We further report evidence that velocity fluctuations are not scale invariant but possess more complex self-similarity properties that are like ly to depend on the Reynolds number. We comment on the possible asymptotic validity of the multifractal description. (C) 1999 Academic Press.