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arXiv 2110.04777math.NAcs.NA
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相容条件下网络非线性流问题的快照模型降阶

On snapshot-based model reduction under compatibility conditions for a nonlinear flow problem on networks

Björn Liljegren-Sailer, Nicole Marheineke

摘要:

本文在网格上构造了带摩擦项的正压欧拉方程的保结构、在线有效的降阶模型。非线性流动问题在天然气分配网络中有着广泛的应用。我们提出了一个基于快照的减少方法,包括一个混合变分伽辽金近似结合正交型复杂性降低。它的主要特点是在训练阶段保证了某些兼容性条件,这使得我们的方法保持了结构。由此得到的降阶模型是局部质量守恒的,并继承了能量束缚和端口哈密顿结构。我们还得到了一个适定性的结果。在训练阶段,相容性条件提出了挑战,我们面临的约束数据近似问题,而不是在传统的约简方法的无约束训练问题。我们的模型降阶的训练由兼容性约束下的主成分分析组成,并且特别地,产生满足快照数据的最优性条件的降阶模型。我们的正交型复杂性降低的训练涉及到一个半定的程序与组合方面,我们接近一个贪婪的过程。

英文摘要:

This paper is on the construction of structure-preserving, online-efficient reduced models for the barotropic Euler equations with a friction term on networks. The nonlinear flow problem finds broad application in the context of gas distribution networks. We propose a snapshot-based reduction approach that consists of a mixed variational Galerkin approximation combined with quadrature-type complexity reduction. Its main feature is that certain compatibility conditions are assured during the training phase, which make our approach structure-preserving. The resulting reduced models are locally mass conservative and inherit an energy-bound and port-Hamiltonian structure. We also derive a well-posedness result for them. In the training phase, the compatibility conditions pose challenges, we face constrained data approximation problems as opposed to the unconstrained training problems in the conventional reduction methods. The training of our model order reduction consists of a principal component analysis under a compatibility constraint and, notably, yields reduced models that fulfill an optimality condition for the snapshot data. The training of our quadrature-type complexity reduction involves a semi-definite program with combinatorial aspects, which we approach by a greedy procedure.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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