Nahed Sihem Bounoua, 1st year PhD student supervised by Élisabeth Lemaire and Pavel Kuzhir, has been awarded the "young researcher best poster" at the 2013 SFP Conference which took place in Marseille from the 1st to the 5th of July 2013.
Abstract of her poster entitled "Viscosity of non-Brownian fiber suspensions" :
Short fibers are commonly used to improve mechanical, thermal or electrical properties of plastics. Optimization of the fabrication processes of reinforced plastics needs to investigate the rheology of suspensions of fibers and their orientation, which rely heavily on the final properties of the composite. However, the study of the flow of semi-dilute or concentrated fiber suspensions poses significant challenges both conceptual and experimental. Indeed, rheological properties are difficult to predict and model due to the strong coupling of the interactions that the fibers undergo, their orientation and flow. From an experimental point of view, rheological properties are difficult to measure upon using conventional rheometry due to the presence of artefacts such as migration that makes the suspension inhomogeneous or wall effects which significantly alter the local fiber orientation. To overcome these difficulties, we plan to perform coupled measurements of viscosity by a local method (PIV)  and of the fiber orientation . Another way to highlight the coupling between the orientation and the viscosity is to perform shear reversal experiments . In this poster, we present our first experimental observations of the behavior of fiber suspensions after shear reversal. These measurements were performed in parallel-plate torsional flow of semi-dilute fiber suspensions for two aspect ratios : 18 and 33 and several values of the gap between the two discs of the rheometer.
 Blanc F. et al., Particle Image Velocimetry in Concentrated Suspensions : Application to Local Rheometry, Appl. Rheol. 21, 23735, 2011
 Jeffery G. B., ‘‘The motion of ellipsoidal particles immersed in a viscous fluid,’’ Proc. R. Soc. London, Ser. A 102, 161-179, 1922.
 Sepehr M. et al., Rheological properties of short fiber model suspensions, J. Rheol. 48, 1023-1048, 2004.
Website of the 2013 SFP Conference.
Fluides & Matériaux Complexes, Doctorants/Post-doctorants, Rhéologie des Suspensions
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