本案例演示高Weissenberg数下粘弹性流体流动计算。流体介质粘度采用Phan Thien-Tanner粘弹性模型，其参数为：

1 案例描述

案例轴对称几何模型如下图所示。尺寸x=[0, 4], y = [-20, 20]。入口及出口体积流量Q=3.1415926。

2 Polyflow设置

2.1 读取网格

• 如下图所示导入计算网格contr41.msh

• 双击单元格Setup进入Polydata

2.2 创建Task

• Create Task：F.E.M. task, Evolution, 2D axisymmetric geometry

• Create a subtask: Differential viscoelastic isothermal flow problem

• Domain: Subdomain 1

2.3 定义材料

• 选择Differential viscoelastic models

• 选择1-st viscoelastic model

• 选择Phan Thien-Tanner model

• 设置材料参数visc = 1.0；trelax = 5.0，EVOL: f(S) = S；eps = 0.015；xi = 0.2；ratio = 0.11112

• No density

• no inertia

• no gravity

2.4 边界条件指定

• BS1: Inflow; flow rate = 3.141593 (fully developed, volumetric)

• BS2: vn = vs = 0

• BS3: Outflow; flow rate = 3.141593 (fully developed, volumetric)

• BS4: axis of symmetry

• Interpolation:

• Coordinates: linear

• Stresses: 4x4 SU for element

• Velocities: quadratic

• Pressure: linear

2.5 指定压力与流函数

• 进入F.E.M Task 1面板，如下图所示

• Assign the pressure:

• p=0，坐标(0, 20)

• Assign the stream function:

• ψ = 0 ，坐标 (4, -20)

2.6 指定数值参数

• Evolution parameters:

• Initial value of S = 0

• Upper limit of S = 1

• Initial value of delta-S = 0.01

• Min. admissible value of delta-S = 0.0001

• Max. admissible value of delta-S = 0.25

• Max. number of successful steps = 20

• Implicit Euler method for the integration

2.7 Output

• Default output : CFD-Post

• System of units for CFD-Post: metric_mm/ g/ s/ A+Celsius

3 计算结果

• 速度分布

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