Gabriel Katul, Brani Vidakovic, and John Albertson
June 1999
{\bf Abstract.} High frequency longitudinal velocity ($u$) measurements were performed in the atmospheric boundary layer to investigate the inertial subrange structure of turbulence. Global and local scaling exponent distributions and other statistical properties were derived using continuous (${\cal CWT}$) and critically sampled orthonormal (${\cal OWT}$) wavelet transformations. These statistical measures were contrasted to similar statistical measures derived by applying ${\cal CWT}$ and ${\cal OWT}$ to a fractional Brownian motion ({\it fBm}) time series with a Hurst exponent of $1/3$. This study demonstrated that both ${\cal CWT}$ and ${\cal OWT}$ were able to resolve intermittency-based departures from global power-laws observed in higher-order structure functions. Particularly, the global power laws inferred from ${\cal OWT}$ were in excellent agreement with the She-L\'ev\^eque vortex filament model. However, these wavelet computed intermittency departures were smaller than those computed by the extended self similarity structure function approach. The effects of vortex stretching on the dimensionless structure skewness were well captured by ${\cal CWT}$ and ${\cal OWT}$ coefficients. However, the ${\cal CWT}$ was not able to discern any fundamental differences in the $u$ and {\it fBm} local scaling exponent distributions.
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