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PDE与DAE耦合系统求解方法

The Method of Solving PDE and DAE Coupling System

  • 摘要: 针对目前Modelica语言只能解决由微分代数方程(DAE)描述的问题,而不能解决由偏微分方程(PDE)表达的问题,提出一种求解PDE与DAE耦合系统的方法.首先采用径向基函数构造近似函数,将未知量场函数的时空变量分开;然后运用配点法对空间变量进行离散,从而将PDE问题转化为DAE问题;最后采用成熟的DAE求解器进行求解,得到场函数在任意时空点的函数值.实例结果表明,该方法在不改变Modelica语法的前提下,能较好地实现PDE与DAE耦合系统的一致求解,且求解精度高、稳定性好、边界条件处理简单.

     

    Abstract: Modelica is a multi-domain unified modeling language for modeling and simulation of large and complex physical systems.However, it deals only with differential-algebraic equation (DAE) and no partial differential equation (PDE) .A method of solving PDE and DAE coupling system was presented.The unknown field function of PDE was first approximated with a radial basis function with the form of temporal-spatial variables separation.Then the space variables of PDE were discretized by the collocation method and thus, the PDE was transformed into a series of DAEs.The coupling system was finally solved by the mature DAE solver in MWorks platform based on Modelica.The value of field function at any time-space point was obtained.Resultsshow that this method realizes the consistent solution of PDE and DAE coupling system under the premise of not changing the Modelica grammar, and has high accuracy, good stability, and the convenience of dealing with boundary conditions.

     

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