计算物理 ›› 2014, Vol. 31 ›› Issue (3): 285-291.

• 研究论文 • 上一篇    下一篇

Navier-Stokes方程的最小二乘等几何方法

陈德祥1, 徐自力1, 刘石2, 冯永新2   

  1. 1. 西安交通大学航天航空学院机械结构强度与振动国家重点实验室, 西安 710049;
    2. 广东电网公司电力科学研究院, 广州 510080
  • 收稿日期:2013-07-14 修回日期:2013-12-15 出版日期:2014-05-25 发布日期:2014-05-25
  • 作者简介:陈德祥(1979-),男,博士生,研究方向:等几何分析理论及应用、透平机械强度与振动,E-mail:cdx97@tom.com
  • 基金资助:
    国家973计划(2011CB706505)资助项目

Least Squares Isogeometric Analysis for Navier-Stokes Equations

CHEN Dexiang1, XU Zili1, LIU Shi2, FENG Yongxin2   

  1. 1. State Key Lab for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an 710049, China;
    2. Electric Power Research Institute of Guangdong Power Grid Corporation, Guangzhou 510080, China
  • Received:2013-07-14 Revised:2013-12-15 Online:2014-05-25 Published:2014-05-25

摘要: 基于Hermite多项式的C1型单元构造复杂,限制了最小二乘有限元法的应用.引入高阶光滑的非均匀有理B样条作为基函数简化C1型单元构造,提出求解黏性不可压流动Navier-Stokes方程的最小二乘等几何方法.用Newton法或Picard法对Navier-Stokes方程线性化,用线性化偏微分方程的余量定义最小二乘泛函,导出最小二乘变分方程,用NURBS构造高阶光滑的有限维空间来近似速度场和压力场.计算表明:本文方法计算的二维顶盖驱动流数值解能准确描述流动状况,计算的二维通道内圆柱绕流全局质量损失由最小二乘有限元法的6%降为0.018%,该方法可用于Navier-Stokes方程的求解,并且具有较好的质量守恒性.

关键词: 最小二乘法, 等几何分析, Navier-Stokes方程, NURBS, 有限元

Abstract: With high order smooth non-uniform rational B-splines (NURBS) as basis function to simplify C1 element construction, least squares isogeometric analysis is proposed for viscous incompressible Navier-Stokes equations. Governing equations are linearized by Picard or Newton method. Variational equation is derived from least squares functional defined by residuals of linearized equations. High order smooth finite dimensional spaces for velocity and pressure approximation are constructed by NURBS. Two benchmark flow problems were solved. Accurate numerical results were obtained for 2-dimensional lid driven flows. Global mass loss in flow past a cylinder in a channel decreased from 6% in classical least squares finite element method to 0.018%. It shows that the method is applicable to Navier-Stokes equations. It is better in mass conservation than least squares finite element method.

Key words: least squares, isogeometric analysis, Navier-Stokes equation, NURBS, FEM

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