Jaan Kalda

Séminaire régulier
Tallinn Technical University, Estonie

Fully developed turbulence is known to be highly intermittent, characterized by non-Gaussian statistics and non-vanishing probabilities of extreme events. This intermittency results e.g. in anomalous scaling of structure functions, and small-scale anisotropy of passive tracer fields. We present a novel simple model for the evolution of passive tracers in turbulent flows. Based on that model, we derive an expression for the structure function scaling exponent (which is in a good agreement with existing numerical and experimental data), and reveal the origin of the small-scale anisotropy. The model can be adapted and extended to study a wide spectrum of problems, related to turbulent transport and mixing, both numerically and analytically. In particular, we anticipate a major progress in understanding the rain initiation process in warm clouds.