Author: toschi
Kim Alards
Lagrangian analysis of rotating Rayleigh-Bénard turbulence
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Kim
Dynamics of particles in cylindrical rotating Rayleigh-Bénard convection (RRBC) is studied using DNS, not only to understand the physics of RRBC, but also to investigate whether particles with a feedback reaction on the flow can influence the dynamics within the cell.
Lagrangian statistics is used to characterise flow structures and heat transport and statistics obtained in the cell center and near the top- and bottom plates are compared to study the role of boundary layers in RRBC. The cylindrical set-up moreover allows us to compare results directly to particle-tracking experiments in RRBC.
On top of Lagrangian statistics also clustering dynamics of particles with different properties, such as thermal inertia and buoyancy, is investigated. By including both mechanical and thermal two-way coupling we can analyse the influence of particles on the flow and study whether we can trigger a transition to enhanced heat transport, which can be beneficial for industrial applications.
Alumni master students
2009 Alessandro Candini, Erasmus placement (University of Ferrara).
2010 Francesca Mancini, Erasmus student (University of Tor Vergata).
2010 Andrea Donini, Erasmus student (University of Udine)
2010 Enrico Pitton, Erasmus student (University of Udine)
2010 Riccardo Scatamacchia, Master student (University of Tor Vergata)
2011 Alessandro Dal Cin, Erasmus student (University of Udine)
2012 Eros Pecile, Erasmus student (University of Udine).
2012 Salvatore Lovecchio, master student (University of Udine).
2012 Simone Fisci, master student (University of Udine).
2012 Davide Picchi, master student (University of Brescia).
2013 Mauro Feletto, master student (University of Udine).
2013 Luca del Maschio, master student (University of Udine).
2013 Giulio de Magistris, master student (University of Roma Tor Vergata).
2014 Abdallah Daddi Moussa Ider, master student (University of Marseille, France).
2014 Kim Alards, master student (Eindhoven University of Technology).
2016 Koen Arens, master student (Eindhoven University of Technology).
2016 Jasper Meeusen, master student (Eindhoven University of Technology).
Abhineet Gupta
Photo-bioreactors: saving algae from turbulence!
Understanding turbulent flow of (dense) suspensions is one of the key factors needed in order to upscale and thus increase the productivity of algae photo-bioreactors. Many studies investigated the rheology of dense suspensions in laminar flows, as well as the dynamics of dilute suspensions in turbulence. We study dense suspension of finite size particles (algae) under turbulent flow conditions using a Lattice Boltzmann solver. Direct numerical simulations will be used to assess the level of hydrodynamics stresses on individual algae. The knowledge of the multi-scale statistics of turbulent fluctuations, down to the individual alga, is key to develop models necessary to up-scale photo-bioreactor, select algae strain, optimize algae productivity and reduce bioreactors energy consumption.
Riccardo Scatamacchia
Extreme Events in the Dispersions of Two Neighboring Particles Under the Influence of Fluid Turbulence
Phys. Rev. Lett. 109, 144501 – Published 5 October 2012
R. Scatamacchia, L. Biferale, and F. Toschi
ABSTRACT
We present a numerical study of two-particle dispersion from point sources in three-dimensional incompressible homogeneous and isotropic turbulence at Reynolds number Re≃300. Tracer particles are emitted in bunches from localized sources smaller than the Kolmogorov scale. We report the first quantitative evidence, supported by an unprecedented statistics, 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 correct viscous-, inertial-, and integral-scale properties, allows us to assess the importance of temporal correlations along tracer trajectories.