共查询到6条相似文献,搜索用时 3 毫秒
1.
We suggest a scalar model for deformation and flow of an amorphous material such as a foam or an emulsion. To describe elastic,
plastic and viscous behaviours, we use three scalar variables: elastic deformation, plastic deformation rate and total deformation
rate; and three material-specific parameters: shear modulus, yield deformation and viscosity. We obtain equations valid for
different types of deformations and flows slower than the relaxation rate towards mechanical equilibrium. In particular, they
are valid both in transient or steady flow regimes, even at large elastic deformation. We discuss why viscosity can be relevant
even in this slow shear (often called “quasi-static”) limit. Predictions of the storage and loss moduli agree with the experimental
literature, and explain with simple arguments the non-linear large amplitude trends. 相似文献
2.
H. Caps H. Decauwer M.-L. Chevalier G. Soyez M. Ausloos N. Vandewalle 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):115-119
We report an experimental study of aqueous foam imbibition in microgravity with strict mass conservation. The foam is in a
Hele-Shaw cell. The bubble edge width ℓ is measured by image analysis. The penetration of the liquid in the foam, the foam
imbibition, the foam inflation, and the rigidity loss are shown all to obey strict diffusion processes. The motion of bubbles
needed for the foam inflation is a slow two-dimensional process with respect to the one-dimensional capillary rise of liquid.
The foam is found to imbibes faster than it inflates.
Received 20 May 2002 / Received in final form 21 January 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: herve.caps@ulg.ac.be 相似文献
3.
We have examined a number of candidates for the minimum-surface-energy arrangement of two-dimensional clusters composed of
N bubbles of area 1 and N bubbles of area λ ( λ≤1). These include hexagonal bubbles sorted into two monodisperse honeycomb tilings, and various mixed
periodic tilings with at most four bubbles per unit cell. We identify, as a function of λ, the minimal configuration for N → ∞. For finite N, the energy of the external (i.e., cluster-gas) boundary and that of the interface between honeycombs in “phase-separated” clusters have to be taken into account.
We estimate these contributions and find the lowest total energy configuration for each pair (N,λ). As λ is varied, this alternates between a circular cluster of one of the mixed tilings, and “partial wetting” of the
monodisperse honeycomb of bubble area 1 by the monodisperse honeycomb of bubble area λ.
Received 1 August 2002
RID="a"
ID="a"e-mail: paulo@ist.utl.pt 相似文献
4.
J.-F. Berret R. Gamez-Corrales S. Lerouge J.-P. Decruppe 《The European physical journal. E, Soft matter》2000,2(4):343-350
We report on the shear-thickening transition observed in dilute aqueous solutions of cetyltrimethylammonium tosylate (CTAT)
at concentrations . We have re-examined the kinetics of the shear-thickening transition using start-up experiments at rates above the critical
shear rate . Using simple well-defined protocols, we have found that the transient mechanical response depends dramatically on the thermal
and on the shear histories. Using the same protocols, flow birefringence experiments were carried out. The gap of a Couette
cell containing the sheared solution has been visualized between crossed polarizers in steady shear conditions, as well as
in start-up experiments. We show that the birefringent shear-induced phase starts from the inner cylinder and grows along
the velocity gradient direction, as in a shear banding situation. However, around we have not observed a regime of phase coexistence (isotropic and birefringent).
Received 11 November 1999 相似文献
5.
Column size effects of DER fluids 总被引:1,自引:0,他引:1
The static yield stress of dielectric electrorheological (DER) fluids of infinite column state and chain state are calculated
from the first principle method. The results indicate that the column surface contributions to ER effects is very small and
both states will give correct results to the real DER fluids.
Received 29 January 2001 and Received in final form 30 April 2001 相似文献
6.
Bellour M Skouri M Munch JP Hébraud P 《The European physical journal. E, Soft matter》2002,8(4):431-436
We have measured the mean-square displacement of colloidal particles embedded in a semi-dilute solution of worm-like micelles,
using diffusing wave spectroscopy. This allowed us to describe their rheological properties over a very wide time range. At
very short times, the particles diffuse freely in the solvent, and then, they experience the characteristic relaxation times
of the living chains. We deduced directly, from the mean-square displacement of the particles, the mechanical properties of
the micellar solution, not only in the high-frequency regime, but also in the low-frequency range, in which we compared our
results with direct mechanical measurements, and found good agreement.
Received 22 March 2002 and Received in final form 5 June 2002 相似文献