Presenter: Alfredo Soldati

Turbulent flows with suspended anisotropic particles are a common occurrence in many industrial (e.g. papermaking, pharmaceutical processing, soot emission) and natural processes (e.g. pollen species, icy clouds, and plankton and marine snow). If particles are small enough (Order of Kolmogorov scales) their dynamics is dominated by the velocity gradient tensor of the flow, and the analysis of their motion can be instrumental to characterize the flow field dynamics. Therefore, practical and foundational aspects characterize this problem, which we investigate by means of a fully controlled experimental channel equipped with an array of high-speed cameras. Results will be presented elaborating on the full dynamics of small non-axisymmetric– quasi-straight to slightly curved – fibres and on the local flow field.  We will highlight the role of fibers curvature on spinning and tumbling rates and we will propose conceptual models and scalings laws.