The formulation for the flow model is given using the finite element / control volume ( fe / cv ) technique based on darcy ' s law of creeping flow through a porous media . the heat transfer model is based on the two - dimensional , transient heat conduction equation , including heat generation . the cure kinetics model is based on kamal ' s model , and the degree of the resin cure as a function of temperature and time 树脂流动阶段的模拟是根据牛顿流体在多孔介质中的渗流理论,应用darcy定律并使用有限元/控制体技术建立起来的;热传递模型是一个二维瞬态热传导方程,考虑树脂反应放热;树脂的固化模型利用了kamal提出的固化动力学方程,将固化度取为时间和温度的函数。
In the numerical methods section , a finite element / control volume mold filling simulation , a tensor representation of fibre orientation and a finite element solution of the transient fibre orientation equations are combined in the program . the input data and output results are visualized by means of finite element software 程序中用有限单元控制体方法模拟模压流动,用表征纤维取向的张量和有限元伽辽金方法来解决瞬时纤维取向方程,用计算机图形原理编程实现对smc流动轨迹、纤维取向分布的计算机模拟。
According to the movement traces of yarn carriers on the braiding machine bed , a perform was divided into three regions , i . e . interior , surface and corner , and distinct control volumes were defined for each region . analyzing the control volume of each region , the yarn architecture of perform was described and three kinds of local unit cell were identified . then the relations between the braiding parameters of the perform were derived 根据编织过程中携纱器的运动轨迹特点,将预成形件划分为三个不同的区域,分别定义了不同的控制体积单元,识别了预成形件的两种局部单胞模型,分析了预成形件的纱线构造,并导出了编织结构参数之间的关系,同时给出三维编织复合材料的设计方法。
For convenience of grid refinement implementation the nonstaggered grid system based on the structured orthogonal grid scheme is adopted . in order to eliminate the possible pressure wiggles when nonstaggered grid is used , except for the use of the momentum interpolation method ( small wiggles still appear when the method is adopted alone ) , a new method is proposed and applied in the same time . in the new method a pressure - gradient difference term is added to the flow velocity in each control volume interface when dealing with the pressure - correction equation 本文基于结构化正交网格,为便于实施网格加密,采用了变量同位存储的同位网格体系;为平抑该网格体系下的压力振荡问题,除采用动量插值方法外(单纯采用该方法不能完全平抑振荡) ,首次提出了在压力校正方程的界面流速中添加压力梯度差值项的方法,从而完全解决了建筑风场模拟中同位网格下可能出现的不合理压力场的问题。
The purpose of this dissertation is to study the lagrangian method and conservative rezonning algorithm . finite volume scheme is used for lagrangian equations of hydrodynamics . because of the pressure gradients " influence upon velocities and energy , computational scheme is proposed for momentum equation on two control volumes in order to suspend the time when the mesh becomes distorted 本文的目的是研究lagrange方法及重映算法,主要内容可分为以下几个方面:首先从积分形式的二维lagrange流体力学方程组出发,用有限体积格式进行计算,考虑压力梯度分布对速度和能量改变的影响,构造了在两个控制体上的动量方程的计算格式,使得速度的改变受其周围八个压力的影响,在一定程度上推迟了网格相交的进程。
In fluid mechanics and thermodynamics, a control volume is a mathematical abstraction employed in the process of creating mathematical models of physical processes. In an inertial frame of reference, it is a volume fixed in space or moving with constant velocity through which the fluid (gas or liquid) flows.