基于聚合物分子运动论,提出了一种新的计算聚合物流体的多尺度方法.该方法在宏观尺度上应用无网格方法求解速度场,在微观尺度上应用随机模拟技术计算聚合物对应力的贡献,从而避免需要本构方程来封闭连续性方程和动量守恒方程.对Hooke哑铃模型、FENE哑铃模型、FENE-P哑铃模型,模拟了突然起动平面Couette流动;对Hooke哑铃模型,模拟了方腔驱动流动.从而验证了该方法的有效性和计算结果的可靠性.
Based on simulation of molecular models of polymeric fluids, a new micro-macro method for numerical calculation of viscoelastic flow is presented in this paper. This method coupled the mass and momentum conservation equations at the macroscopic level, with a stochastic differential equation which models the evolution of the polymer configures at the microscopic level. Accordingly, the velocity filed was determined by solving the conservation equation with a meshless method, and the stress was computed from the molecular configuration rather than from closed-form constitutive equations. Thus this method bypassed the need for a rheological constitutive equation to describe the polymeric fluid. In order to validate this method and to demonstrate its robustness, the start-up planar Couette flow was studied for Hookean, FENE and FENE-P dumbbell models and the lid-driven cavity flow was studied for Hookean dumbbell models.