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【答案】应助回帖
感谢参与,应助指数 +1
Finite volume method
Main article: Finite volume method
The finite volume method (FVM) is a common approach used in CFD codes.[citation needed] The governing equations are solved over discrete control volumes. Finite volume methods recast the governing partial differential equations (typically the Navier-Stokes equations) in a conservative form, and then discretize the new equation. This guarantees the conservation of fluxes through a particular control volume. The finite volume equation yields governing equations in the form,
where is the vector of conserved variables, is the vector of fluxes (see Euler equations or Navier–Stokes equations), is the volume of the control volume element, and is the surface area of the control volume element.
[edit]Finite element method
Main article: Finite element method
The finite element method (FEM) is used in structural analysis of solids, but is also applicable to fluids. However, the FEM formulation requires special care to ensure a conservative solution. The FEM formulation has been adapted for use with fluid dynamics governing equations.[citation needed] Although FEM must be carefully formulated to be conservative, it is much more stable than the finite volume approach[4] However, FEM can require more memory than FVM.[5]
In this method, a weighted residual equation is formed:
where is the equation residual at an element vertex , is the conservation equation expressed on an element basis, is the weight factor, and is the volume of the element.
[edit]Finite difference method
Main article: Finite difference method
The finite difference method (FDM) has historical importance[citation needed] and is simple to program. It is currently only used in few specialized codes.[citation needed] Modern finite difference codes make use of an embedded boundary for handling complex geometries, making these codes highly efficient and accurate.[citation needed] Other ways to handle geometries include use of overlapping grids, where the solution is interpolated across each grid.
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