arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.11835math.NAcs.NA
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区域分解最小二乘Petrov-Galerkin(DD-LSPG)非线性模型降阶

Domain-decomposition least-squares Petrov-Galerkin (DD-LSPG) nonlinear model reduction

Chi Hoang, Youngsoo Choi, Kevin Carlberg

摘要:

一种新的区域分解最小二乘Petrov-Galerkin(DD-LSPG)模型降阶法,适用于非线性代数方程的参数化系统(例如,由离散化参数化偏微分方程问题引起)。与以往的工作相比,我们采用了代数非重叠的分解策略,而不是空间分解策略,这有利于应用到不同的空间离散化计划。该方法不是以单片方式为整个状态空间构建低维子空间,而是为表征原始模型的不同子域/组件构建单独的子空间。在离线阶段,该方法构造低维基的内部和接口的组件。在联机阶段,该方法为每个组件构建一个LSPG ROM,并在连接它们的“端口”上强制执行强兼容性或弱兼容性。我们提出了四种不同的方法来构建减少基地的接口/端口的子域和几种方法来加强跨连接端口的兼容性。我们推导了DD-LSPG解的后验和先验误差界。在传热和流体动力学中的非线性基准问题上进行的数值结果表明,所提出的方法在精度和计算成本方面都表现良好,不同的基础和兼容性约束的选择产生不同的性能曲线。

英文摘要:

A novel domain-decomposition least-squares Petrov-Galerkin (DD-LSPG) model-reduction method applicable to parameterized systems of nonlinear algebraic equations (e.g., arising from discretizing a parameterized partial-differential-equations problem) is proposed. In contrast with previous works, we adopt an algebraically non-overlapping decomposition strategy rather than a spatial-decomposition strategy, which facilitates application to different spatial-discretization schemes. Rather than constructing a low-dimensional subspace for the entire state space in a monolithic fashion, the methodology constructs separate subspaces for the different subdomains/components characterizing the original model. In the offline stage, the method constructs low-dimensional bases for the interior and interface of components. In the online stage, the approach constructs an LSPG ROM for each component and enforces strong or weak compatibility on the 'ports' connecting them. We propose four different ways to construct reduced bases on the interface/ports of subdomains and several ways to enforce compatibility across connecting ports. We derive a posteriori and a priori error bounds for the DD-LSPG solutions. Numerical results performed on nonlinear benchmark problems in heat transfer and fluid dynamics demonstrate that the proposed method performs well in terms of both accuracy and computational cost, with different choices of basis and compatibility constraints yielding different performance profiles.

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