CGCOMPLEXFLUIDFLOW · Systematic and thermodynamically consistent coarse graining the flow of complex fluids
FP7 — People (Marie Curie Actions)
- Duration
- 2014-03-01 → 2018-02-28
- EU contribution
- €100,000
- Participants
- 1
- Scheme
- MC-CIG
Lines connect the coordinator with its partners.
Results in brief
Systematic and thermodynamically consistent coarse graining the flow of complex fluids
Derivation of macroscopic constitutive equations from underlying microscopic model systems is at the core of nonequilibrium statistical mechanics. In the context of soft matter in general and polymer and liquid-crystal physics in particular, this classical problem has seen renewed interest not least due to new and fascinating applications in smart materials. In this project, we investigate coarse-graining approaches for two microscopic model systems of nematic liquid crystals: the Lebwohl-Lasher spin lattice system as well as an off-lattice systems of rigid ellipsoids interacting via the Gay-Berne potential. As collective variable, we choose the orientational order parameter tensor. A cornerstone of the macroscopic theory of liquid crystals is the Landau-de Gennes free energy. Rather than postulating the Landau-de Gennes free energy, we were able to establish a link between this effective free energy and a large deviation function. Using Chernoff's formula allows us to determine the latter numerically and to reduce the numerical uncertainties compared to earlier approaches. Furthermore, we showed for the Lebwohl-Lasher model the equivalence of the projection operator approach to a more traditional, Kirkwood-like method of coarse graining. Special emphasis we paid on the resulting time correlation functions of fluctuations that play a central part in determining macroscopic properties. Interestingly, we find propagating modes and long-time tails in the angular momentum correlations. More information and the corresponding publications can be found under http://www.personal.reading.ac.uk/~sg906606/CGcomplexfluidflow.html or directly contacting Patrick Ilg via email: p.ilg@reading.ac.uk.
Data: CORDIS, © European Union
Project objective
The overall aim of this project is to develop a systematic and thermodynamically consistent method to derive macroscopic constitutive equations from molecular models of polymeric and anisotropic fluids.Since the constitutive equations describe the transport and flow behavior of the material on a coarse-grained level, many phenomenological approaches have been proposed in the past. The method we will develop here combines projection operator techniques and simulations within a nonequilibrium thermodynamics framework. Novel, thermodynamically guided simulations will allow us to identify building blocks of the macroscopic model and thereby establish the macroscopic constitutive equations in a thermodynamically consistent form. The systematic coarse-graining approach is therefore well-founded and applicable to a wide variety of systems. The systematic nature of the proposed method allows us to investigate different levels of coarse graining where different amounts of information are kept in the coarser model. For each of the coarse-grained models we will determine their range of validity and thereby identify the appropriateness of the chosen level of description. The result of these works is a hierarchy of models - a truly multi-scale modelling of the system - which includes only the relevant set of variables needed on the chosen level of description.We will develop and illustrate the method for the important case of polymeric and anisotropic fluids like liquid-crystals and ferrofluids. Many concepts of soft matter physics have been established for these systems. Moreover, transport and flow properties of polymeric and anisotropic fluids are also very interesting for industrial and food processing, as well as in biological environments. In view of these applications, we also plan to develop multi-scale simulations where we combine a finer and coarser model that we have already consistently related before, e.g. to study interface effects on bulk transport behavior.
Original text from CORDIS.
Participants
- THE UNIVERSITY OF READING · ReadingCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union