Special Seminar: Spring 2013
Speaker: Dr. Luca Biferale (University of Rome "Tor Vergata”)
Title: "Particles Separations in Turbulent Flows: Extreme Events"
Date: Tuesday, March 19, 2013
Time: 12:00 p.m. (noon)
Location: Gilman Hall 132
We present a numerical study of two-particle dispersion from point sources in three-dimensional incompressible homogeneous and isotropic turbulence at Reynolds number, 300. Tracer particles are emitted in bunches from localized sources smaller than the Kolmogorov scale. We report a quantitative evidence of the deviations of relative dispersion from Richardson’s picture.
Deviations are due to extreme events of pairs separating much faster than average, and of pairs remaining close for long time. The two classes of events are the fingerprints of complete different physics, the former dominated by inertial subrange and large-scale fluctuations, and the latter by dissipation subrange. A comparison of the relative separation in surrogate white-in-time velocity field, with realistic viscous-, inertial-, and integral-scale properties, allows us to assess the importance of temporal correlations along tracer trajectories. Some preliminary results about the role played by particles' inertia will also be presented.
Dr. Biferale is an Associate Professor of Theoretical Physics at the University of Rome "Tor Vergata". He is involved in numerical and theoretical studies of complex flows with and without particles using both pseudo-spectral high resolution numerical simulations and Lattice Boltzmann methods.