Publications (88) View all
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Article: Multifractal temperature and flux of temperature variance in fully developed turbulence
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ABSTRACT: We analyse the multifractal properties of the temperature field θ and temperature variance flux χ in atmospheric turbulence, using simultaneous velocity V and temperature measurements in the atmosphere. This permits us first to characterize the multifractal scaling moment function of the flux of temperature variance estimated as χ ≈ (Δθ)2ΔV/ℓ. We then study the structure function scaling exponent of the temperature field directly, and compare it to the consequences of the assumption of the independence of the fluctuations of θ and V. Up until moment orders of at least order 6, the data analysis is consistent with independence.EPL (Europhysics Letters) 01/2007; 34(3):195. · 2.17 Impact Factor -
Article: Direct investigation of the K-transport equation for a complex turbulent flow
Journal of Turbulence 01/2003; 4:021. · 0.99 Impact Factor -
Article: Stochastic equations generating continuous multiplicative cascades
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ABSTRACT: Discrete multiplicative turbulent cascades are described using a formalism involving infinitely divisible random measures. This permits to consider the continuous limit of a cascade developed on a continuum of scales, and to provide the stochastic equations defining such processes, involving infinitely divisible stochastic integrals. Causal evolution laws are also given. This gives the first general stochastic equations which generate continuous multifractal measures or processes.03/2001; -
Article: A causal multifractal stochastic equation and its statistical properties
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ABSTRACT: Multiplicative cascades have been introduced in turbulence to generate random or deterministic fields having intermittent values and long-range power-law correlations. Generally this is done using discrete construction rules leading to discrete cascades. Here a causal log-normal stochastic process is introduced; its multifractal properties are demonstrated together with other properties such as the composition rule for scale dependence and stochastic differential equations for time and scale evolutions. This multifractal stochastic process is continuous in scale ratio and in time. It has a simple generating equation and can be used to generate sequentially time series of any length.Physics of Condensed Matter 06/2003; · 1.53 Impact Factor -
Conference Proceeding: Stochastic properties of the water level time series in the Eastern English channel, France
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ABSTRACT: We consider here water level time series recorded in the Eastern English Channel by the SHOM (Service Hydrographique et Oceanographique de la Marine, France) in the port of Dunkerque, every hour from 1956 to 2010. Water level change is a complex phenomenon, influenced by deterministic astronomic forcing (tides, daily cycle, etc.) and also by stochastic forcing: water temperature, atmospheric pressure, turbulence. The deterministic forcings are strong and can be used to reconstruct synthetic water level predictions, also provided hourly by the SHOM. Stochastic forcing exist at all scales from minutes to centuries. Here we use the two datasets to explore the statistical and dynamical properties of both series, deterministic reconstruction and experimental measurements. We estimate power spectra, and return times statistics for different water level thresholds. Applications of this study belong to littoral flood risk assessments.AGU Fall Meeting 2012, San Fransisco; 12/2012
