Non-Spherical Particles and Aggregates in Fluid Flows

June 17, 2013 — June 21, 2013

Coordinators:

  • Federico Toschi (Eindhoven University of Technology, The Netherlands)
  • Cristian Marchioli (Università di Udine, Italy)

Dynamics of non-spherical particles and aggregates in fluid flow are encountered both in nature and in industrial applications. Examples for non-spherical particles include airborne solid particles or aerosols, carbon nanotubes, micro-organisms like phytoplankton, sediment-laden flows and wood-fibre suspensions. Particle aggregates are found in chemical, industrial or material processes for colloids and in polymer manufacturing. In these processes, particle size ranges from several nanometers to several centimeters, with loadings that may substantially change the macroscopic (rheological) properties of the suspension flow. On the other hand, transport and interaction of particles/aggregates in complex (e.g. turbulent) flows is governed by a number of physical processes occurring at a wide range of different scales. The rapidly increasing computational power has recently made feasible three-dimensional, time-dependent simulations of non-ideal particles in fluid flows, producing an entire branch of flourishing literature which is fostering research in dispersed multiphase flow. Progress has been substantial also from an experimental viewpoint, with improved measurement techniques based on optics or magnetic resonance flow imaging. Due to the multiscale nature of the problem, investigation and modelling require synergetic use of such approaches.
Objective of the course is to provide a general and unified frame of the current research on the dynamical behaviour of non-spherical particles and particle aggregates in complex flows and put future research paths in perspective. The focus will be on generic aspects and physics of non-ideal particle suspensions (e.g. rheological properties in suspensions of anisotropic deformable particles, and modulation of turbulence induced by particles/aggregates). Issues related to modelling and physical understanding at all various length scales will be covered: from the scale resolving the complex flow around individual non-spherical particles, to large eddy simulation models for flows with particles, to large-scale Eulerian-Eulerian models. Among the topics to be included are particle dynamics in free and wall-bounded turbulence, fluid-particle interactions, collision modelling, break-up and agglomeration, advances in measurement and simulation techniques, and rheological modelling.
The lectures will also provide a wide overview of cutting-edge work in this very active area of multiphase flow research and focus in more detail on a few advanced topics of significant practical and theoretical value in several areas of engineering and applied physics. This will reinforce understanding of the fundamental phenomena and their importance, providing participants with varied conceptual and methodological tools applicable to problems at hand. After the lectures, students should possess the necessary knowledge of the basic capabilities, potentials and limitations of the various numerical and experimental methods taught and, hence, should be able to critically evaluate the reliability and accuracy of the information these methods can provide when applied to practical situations.


The course delivers a comprehensive overview of non-ideal particle/aggregate dynamics in complex fluids, and hence will be particularly attractive to graduate students, PhD candidates, young researchers and faculty members in applied physics and (chemical, mechanical) engineering. The advanced topics and the presentation of current progress in this very active field will also be of considerable interest to many senior researchers, as well as industrial practitioners having a strong research interest in understanding the multi-scale complex behavior of such multiphase flows, with particular emphasis on turbulent flows.


Workshop session on Thursday will be led by Marco Vanni (Politecnico di Torino, Italy) and by Bernhard Mehlig (Goteborg University, Sweden) on “Numerical simulation of agglomeration and aggregate dynamics: modelling of particle collision and agglomeration in turbulent flows” and on “Tumbling of non-spherical particles in random flows”.


The course will be organized under the auspices of ERCOFTAC’s SIG12 “Dispersed Turbulent Two-Phase Flows” and SIG43 “Fiber suspension flow modelling” and with the support of two COST Actions: Action FP1005 “Fiber suspension flow modelling: a key for innovation and competitiveness in pulp & paper industry” and Action MP0806 “Particles in Turbulence”.

KEYWORDS:
Non spherical particles, Aggregates of particles, Euler/Lagrange methods, DNS, LES, LBM.

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