Miyazaki Kunimasa, Reichman David R, Yamamoto Ryoichi
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Jul;70(1 Pt 1):011501. doi: 10.1103/PhysRevE.70.011501. Epub 2004 Jul 1.
We analyze the behavior of supercooled fluids under shear both theoretically and numerically. Theoretically, we generalize the mode-coupling theory of supercooled fluids to systems under stationary shear flow. Our starting point is the set of generalized fluctuating hydrodynamic equations with a convection term. A nonlinear integrodifferential equation for the intermediate scattering function is constructed. This theory is applied to a two-dimensional colloidal suspension. The shear rate dependence of the intermediate scattering function and the shear viscosity is analyzed. We have also performed extensive numerical simulations of a two-dimensional binary liquid with soft-core interactions near, but above, the glass transition temperature. Both theoretical and numerical results show the following. (i) A drastic reduction of the structural relaxation time and the shear viscosity due to shear. Both the structural relaxation time and the viscosity decrease as gamma(-nu) with an exponent nu< or =1, where gamma; is the shear rate. (ii) Almost isotropic dynamics regardless of the strength of the anisotropic shear flow.
我们从理论和数值两方面分析了过冷流体在剪切作用下的行为。理论上，我们将过冷流体的模式耦合理论推广到定常剪切流作用下的系统。我们的出发点是带有对流项的广义涨落流体动力学方程组。构建了一个关于中间散射函数的非线性积分微分方程。该理论应用于二维胶体悬浮液。分析了中间散射函数和剪切黏度对剪切速率的依赖性。我们还对接近但高于玻璃化转变温度且具有软核相互作用的二维二元液体进行了广泛的数值模拟。理论和数值结果均表明如下情况。(i) 由于剪切作用，结构弛豫时间和剪切黏度急剧降低。结构弛豫时间和黏度均随γ^(-ν) 减小，指数ν≤1，其中γ为剪切速率。(ii) 无论各向异性剪切流的强度如何，动力学几乎都是各向同性的。
