The stress tensor for a dil. suspension of buoyancy free, inertialess, nonBrownian, rigid spheres immersed in a viscoelastic liq. is detd. via a perturbative expansion. The perturbation parameter is the Deborah no. De, giving the ratio between the characteristic time of the liq. and the characteristic time of the imposed flow. The theor. predictions upto order De are validated through numerical simulations of continuity and momentum equations for the single sphere problem. The analytic expressions for the local fields of velocity, pressure, and stresses are successfully compared with the results obtained with finite element calcns. Bulk rheol. quantities from theory and simulations also show an excellent agreement with each other. Good agreement is found with respect to exptl. data from the literature, e.g., on bulk normal stresses for dil. suspensions in shear flow.
Rheology of a dilute suspension of rigid spheres in a second order fluid / Greco, Francesco; D'Avino, Gaetano; Maffettone, PIER LUCA. - In: JOURNAL OF NON-NEWTONIAN FLUID MECHANICS. - ISSN 0377-0257. - 147:1-2(2007), pp. 1-10. [10.1016/j.jnnfm.2007.06.002]
Rheology of a dilute suspension of rigid spheres in a second order fluid
GRECO, FRANCESCO;D'AVINO, GAETANO;MAFFETTONE, PIER LUCA
2007
Abstract
The stress tensor for a dil. suspension of buoyancy free, inertialess, nonBrownian, rigid spheres immersed in a viscoelastic liq. is detd. via a perturbative expansion. The perturbation parameter is the Deborah no. De, giving the ratio between the characteristic time of the liq. and the characteristic time of the imposed flow. The theor. predictions upto order De are validated through numerical simulations of continuity and momentum equations for the single sphere problem. The analytic expressions for the local fields of velocity, pressure, and stresses are successfully compared with the results obtained with finite element calcns. Bulk rheol. quantities from theory and simulations also show an excellent agreement with each other. Good agreement is found with respect to exptl. data from the literature, e.g., on bulk normal stresses for dil. suspensions in shear flow.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.