Rheological measurements on a solution undergoing inverse melting are presented as a function of temperature and concentration. Under shear, this solution exhibits the phenomenon of shear thickening; i.e. an increase in apparent viscosity with increasing shear rate (gamma) over dot. In particular, a shear-thickening transition happens at a critical shear rate (gamma) over dot(c), which increases with increasing concentration. It defines two different regimes: at low shear rates (gamma) over dot < (gamma) over dot(c), the fluid shows Newtonian behaviour, while at shear rates (gamma) over dot > (gamma) over dot(c), a transition from the Newtonian to the shear-thickening regime is observed. This behaviour is interpreted on the basis of a relaxation process activated by the shear and characterised by a relaxation time tau = 1/(gamma) over dot(c). In the thickening region, the viscosity data are well fitted with a power-law model eta((gamma) over dot)) = A (gamma) over dot(n-1), with n = 1.8. The temperature and concentration behaviour of the zero shear viscosity, the power-law exponent and the critical shear rate are discussed.

Shear thickening in a solution undergoing inverse melting / R., Angelini; G., Salvi; Ruocco, Giancarlo. - In: PHILOSOPHICAL MAGAZINE. - ISSN 1478-6435. - 88:33-35(2008), pp. 4109-4116. (Intervento presentato al convegno 11th International Workshop on Complex Systems tenutosi a Andalo, ITALY nel MAR 17-20, 2008) [10.1080/14786430802415232].

Shear thickening in a solution undergoing inverse melting

RUOCCO, Giancarlo
2008

Abstract

Rheological measurements on a solution undergoing inverse melting are presented as a function of temperature and concentration. Under shear, this solution exhibits the phenomenon of shear thickening; i.e. an increase in apparent viscosity with increasing shear rate (gamma) over dot. In particular, a shear-thickening transition happens at a critical shear rate (gamma) over dot(c), which increases with increasing concentration. It defines two different regimes: at low shear rates (gamma) over dot < (gamma) over dot(c), the fluid shows Newtonian behaviour, while at shear rates (gamma) over dot > (gamma) over dot(c), a transition from the Newtonian to the shear-thickening regime is observed. This behaviour is interpreted on the basis of a relaxation process activated by the shear and characterised by a relaxation time tau = 1/(gamma) over dot(c). In the thickening region, the viscosity data are well fitted with a power-law model eta((gamma) over dot)) = A (gamma) over dot(n-1), with n = 1.8. The temperature and concentration behaviour of the zero shear viscosity, the power-law exponent and the critical shear rate are discussed.
2008
inverse melting; rheology; shear; shear thickening; viscosity
01 Pubblicazione su rivista::01a Articolo in rivista
Shear thickening in a solution undergoing inverse melting / R., Angelini; G., Salvi; Ruocco, Giancarlo. - In: PHILOSOPHICAL MAGAZINE. - ISSN 1478-6435. - 88:33-35(2008), pp. 4109-4116. (Intervento presentato al convegno 11th International Workshop on Complex Systems tenutosi a Andalo, ITALY nel MAR 17-20, 2008) [10.1080/14786430802415232].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/83567
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