论文标题

使用节点径向基函数求解线性对流方程的一种完全隐式的方法

A fully implicit method using nodal radial basis functions to solve the linear advection equation

论文作者

Gourdain, P. -A., Adams, M. B., Evans, M., Hasson, H. R., Young, J. R., West-Abdallah, I.

论文摘要

当离散化SCHE-ME需要不均匀的节点分布时,通常使用径向基函数。尽管从渴望在随机的节点上插入功能的愿望产卵,但他们在求解许多类型的微分方程方面成功地应用了应用。但是,用于基础函数的线性叠加来插入溶液的插值溶液的重量,解决方案的实际值完全不同。实际上,这些权重将溶液的值与用于离散方程式的节点的几何位置混合。在本文中,我们使用了节点径向基函数,它们是域内每个节点的脉冲函数的插值。这种转换允许使用串联扩展而不是矩阵逆的显式计算来求解线性双曲线偏微分方程。这种转换有效地产生了一个隐式求解器,该求解器仅需要使用矩阵的向量乘法。由于求解器既不需要矩阵逆,也不需要矩阵 - 矩阵产物,因此与其他使用径向基础函数的求解器相比,该方法在数值上更稳定,并且将误差降低至少两个数量级。此外,边界条件直接集成在求解器内部,无需额外费用。该方法自然是保守的,在整个计算过程中几乎保持误差恒定。

Radial basis functions are typically used when discretization sche-mes require inhomogeneous node distributions. While spawning from a desire to interpolate functions on a random set of nodes, they have found successful applications in solving many types of differential equations. However, the weights of the interpolated solution, used in the linear superposition of basis functions to interpolate the solution, and the actual value of the solution are completely different. In fact, these weights mix the value of the solution with the geometrical location of the nodes used to discretize the equation. In this paper, we used nodal radial basis functions, which are interpolants of the impulse function at each node inside the domain. This transformation allows to solve a linear hyperbolic partial differential equation using series expansion rather than the explicit computation of a matrix inverse. This transformation effectively yields an implicit solver which only requires the multiplication of vectors with matrices. Because the solver requires neither matrix inverse nor matrix-matrix products, this approach is numerically more stable and reduces the error by at least two orders of magnitude, compared to other solvers using radial basis functions directly. Further, boundary conditions are integrated directly inside the solver, at no extra cost. The method is naturally conservative, keeping the error virtually constant throughout the computation.

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