Istituto di Scienza e Tecnologie dell'Informazione     
Paradisi P., Cesari R., Allegrini P. Scaling laws of turbulence intermittency in the atmospheric boundary layer: The role of stability. In: IC-MSQUARE - 4th International Conference on Mathematical Modeling in Physical Sciences (Mykonos, Greece, 5-8 June 2015). Proceedings, article n. 012065. (Journal of physics. Conference series, vol. 633). Institute of Physics Publishing, 2015.
Bursting and intermittent behavior is a fundamental feature of turbulence, especially in the vicinity of solid obstacles. This is associated with the dynamics of turbulent energy production and dissipation, which can be described in terms of coherent motion structures. These structures are generated at random times and remain stable for long times, after which they become suddenly unstable and undergo a rapid decay event. This intermittent behavior is described as a birth-death point process of self-organization, i.e., a sequence of critical events. The Inter-Event Time (IET) distribution, associated with intermittent self-organization, is typically a power-law decay, whose power exponent is known as complexity index and characterizes the complexity of the system, i.e., the ability to develop self-organized, metastable motion structures. We use a method, based on diffusion scaling, for the estimation of system's complexity. The method is applied to turbulence velocity data in the atmospheric boundary layer. A neutral condition is compared with a stable one, finding that the complexity index is lower in the neutral case with respect to the stable one. As a consequence, the crucial birth-death events are more rare in the stable case, and this could be associated with a less efficient transport dynamics.
URL: http://iopscience.iop.org/article/10.1088/1742-6596/633/1/012065
DOI: 10.1088/1742-6596/633/1/012065
Subject Turbulence intermittency
Coherent structures
Inter-Event Time distribution
G.3 PROBABILITY AND STATISTICS. Stochastic processes

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