Showing papers on "Shear thinning published in 1976"
TL;DR: In this article, the intrinsic stress contribution from closely-spaced, rod-like rigid particles suspended in a non-Newtonian liquid subject to a simple extensional flow was derived.
Abstract: A formula is derived for the intrinsic stress contribution from closely-spaced, rod-like rigid particles suspended in a non-Newtonian liquid subject to a simple extensional flow. The present results indicate that, compared to the Newtonian-fluid result given previously by Batchelor [1], a much smaller particle-stress effect may occur in non-Newtonian fluid, owing to shear thinning and possible tensile stiffening in the fluid itself. While unsubstantiated by any critical experimental test, this prediction appears to agree qualitatively with some recent experimental observations of Charrier and Rieger [29] on glass fibers in polymer melts. Further work is suggested for the relevant slender-body theory, particularly the far-field body influence in non-linear fluids.
54 citations
TL;DR: The fall in viscosity of many dispersions with increasing shear rate is often attributed to the breaking of links between particles by shear as mentioned in this paper, which is restricted to producing chains in the theories of Cross and of Ruckenstein and Mewis.
13 citations
TL;DR: In this article, a rheometer utilizing the squeeze flow between two parallel circular discs was shown to be successful in characterizing the viscous properties of DMC, and the viscometric data indicated that addition of glass fibers makes the DMC slurry more viscous and shear thinning.
Abstract: Rheological properties of thermosetting glass fiber‐filled Dough Molding Compounds (DMC) are useful in understanding the fiber orientation in moldings caused by flow patterns in the mold as well as in assessing the moldability of the material. A rheometer utilizing the squeeze flow between two parallel circular discs was shown to be successful in characterizing the viscous properties of DMC. The viscometric data indicate that addition of glass fibers makes the DMC slurry more viscous and shear thinning and that the extent of these effects increases with the weight fraction of glass fibers. The length‐to‐diameter ratio of the fibers was found to be an important variable. At the same volume fraction, glass fibers with a larger length‐to‐diameter ratio make the DMC more viscous and shear thinning.
11 citations
TL;DR: In this article, the authors proposed a method for approximating the shear stress/rate-of-strain curve (called here the rheogram) by a series of piecewise continuous linear segments.
Abstract: The treatment of non-linear partial differential equations of unsteady flows of non-Newtonian fluids generally leads to the use of numerical methods. The present method consists in approximating the practical shear stress/rate-of-strain curve (called here the rheogram) by a series of piecewise continuous linear segments. This method involves the solution of the linear differential equation system using a computer. The study is on unsteady laminar flows of pseudoplastic, dilatant and Bingham fluids. The results obtained by this method are compared with those determined by Laser Doppler anemometry using the Bragg cell. The results are concordant.
8 citations
TL;DR: Six commercial fluoride gels have been studied, using a cone and plate viscometer and the thickening agents have been analyzed using infrared spectroscopy, and all gels showed stress thinning, which is the decrease of viscosity with shear rate.
Abstract: Six commercial fluoride gels have been studied, using a cone and plate viscometer. Also, the thickening agents have been analyzed using infrared spectroscopy. All gels showed stress thinning, which is the decrease of viscosity with shear rate. Such shear rate dependence is clinically convenient in that the gel will flow readily at the high shear stresses present when the gel is applied but will not flow readily under its own weight when on the tooth. Five materials containing hydroxyalkyl celluloses showed similar degrees of shear thinning. One material with a non-cellulosic thickener showed much more extreme stress thinning together with elastic behavior at low shear rates; such behavior may be clinically advantageous. All of the gels showed only slight temperature dependence of rheological properties.
7 citations
TL;DR: In this paper, a derivation of viscoelastic fluid theory is given which includes the effect of the entropy dependence upon deformation history, and the resulting theory predicts the observed effects of shear thinning and stress overshoot.
Abstract: A derivation of viscoelastic fluid theory is given which includes the effect of the entropy dependence upon deformation history. The theory is then specialized to model second-order effects. The resulting theory predicts the observed effects of shear thinning and stress overshoot. Comparison is made with experimental data.
5 citations