NG32A-07
ATMOSPHERIC BOUNDARY-LAYER TURBULENCE INTERMITTENCY REVISITED

Wednesday, 16 December 2015: 11:45
300 (Moscone South)
Yacine Mezemate1, George F. Fitton2, Ioulia Tchiguirinskaia3 and Daniel J M Schertzer2, (1)Université Paris-Est, École des Ponts ParisTech, Marne La Vallée, France, (2)Ecole Nationale des Ponts et Chaussées, Champs-sur-Marne, France, (3)U. Paris Est, Ecole des Ponts ParisTech,, Marne-la-Vallee,, France
Abstract:
Turbulence has been and still is the focus of countless experimental, numerical, and theoretical studies. A common physics based approach to complex problems involving extremely large (possibly infinite) degrees of freedom is to consider the possible symmetries of the governing equations. In turbulence, the scaling symmetry of the Navier-Stokes equation justifies a multiple scaling (multifractal) analysis of the phenomena. 
Kolmogorov's famous 1941 hypotheses led to the 2/3rds law (essentially hypothesizing fractal velocity statistics) for the velocity increments and later in 1962 corrected his hypothesis to include an intermittency correction (essentially allowing the velocity to have multiple scaling exponents). 
Both hypotheses have been tested in numerous wind tunnel experiments but empirical validation of the hypotheses in the atmospheric boundary-layer have been difficult due to complex symmetry breaking effects.
Using 50Hz Sonic Anemometer velocity data measured on the site of École des Ponts ParisTech we test Kolmogorov's hypotheses. We find that contrary to numerous wind tunnel testing results, we do not observe a slight increase of the spectral exponent, but a significant decrease this exponent, therefore that intermittency favorise small eddies. We show that it is necessary to reconsider the classical and frequently used assumptions regarding the normalization of the energy flux through scales.
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