101 research outputs found
Response to "Comment on: `Thermodynamics of viscoelastic fluids: the temperature equation'"
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Stress singularities and the formation of birefringent strands in stagnation flows of dilute polymer solutions
We consider stagnation point flow away from a wall for creeping flow of
dilute polymer solutions. For a simplified flow geometry, we explicitly show
that a narrow region of strong polymer extension (a birefringent strand) forms
downstream of the stagnation point in the UCM model and extensions, like the
FENE-P model. These strands are associated with the existence of an essential
singularity in the stresses, which is induced by the fact that the stagnation
point makes the convective term in the constitutive equation into a singular
point. We argue that the mechanism is quite general, so that all flows that
have a separatrix going away from the stagnation point exhibit some singular
behaviour. These findings are the counterpart for wall stagnation points of the
recently discovered singular behaviour in purely elongational flows: the
underlying mechanism is the same while the different nature of the singular
stress behaviour reflects the different form of the velocity expansion close to
the stagnation point.Comment: 15 pages, 6 figure
A European tool for usual intake distribution estimation in relation to data collection by EFSA
The present document has been produced and adopted by the bodies identified above as author(s). In accordance with Article 36 of Regulation (EC) No 178/2002, this task has been carried out exclusively by the author(s) in the context of a grant agreement between the European Food Safety Authority and the author(s). The present document is published complying with the transparency principle to which the Authority is subject. It cannot be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors
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