arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 2603.08765math.NAcs.NA
收藏

一个用于Navier-Stokes-Cahn-Hilliard系统的有限元连续数据同化框架

A finite element continuous data assimilation framework for a Navier--Stokes--Cahn--Hilliard system

Indiana University Bloomington(印第安纳大学布鲁明顿分校)

Tianyu Sun

AI总结:

本文提出了一种用于Navier-Stokes-Cahn-Hilliard系统的有限元连续数据同化框架,通过粗网格观测恢复轨迹并验证其有效性。

摘要:

本文研究了一个耦合的二维Navier-Stokes-Cahn-Hilliard相场模型,该模型附加了一个传输辅助场,并开发了一个连续数据同化(CDA)框架,用于从粗网格观测中恢复其轨迹。我们为耦合NSCH-辅助场模型制定了基于引导的CDA系统,在其中通过一般线性观测算子将粗观测纳入其中。观测机制通过满足H²型近似性质的插值抽象描述,这与通过网格粗化和重构获得的粗空间观测相容。在连续层面上,我们记录了模型的两个结构性质:参考系统的形式能量定律和在同化动力学中的相均值演化定律。在离散层面上,我们引入了一种带有帽的完全离散有限元分裂方案,使用连续二次元素对相、化学势、速度和辅助场进行离散化,同时使用连续线性元素对压力进行离散化。对于该方案,我们证明了一步良好的设定性,并建立了对帽方法的逐步先验估计。数值实验展示了所提出的CDA方法的实际行为。它们展示了从强烈不匹配的初始条件中恢复的能力,并展示了同步如何依赖于观测分辨率、边界驱动和反馈强度。一个粗不可区分实验进一步表明,相同的粗初始信息可能对应于不同的细尺度演化,而同化动力学会选择由提供的时变观测确定的轨迹。

英文摘要:

This paper studies a coupled two-dimensional Navier--Stokes--Cahn--Hilliard phase-field model augmented by a transported auxiliary field, and develops a continuous data assimilation (CDA) framework for recovering its trajectories from coarse-in-space observations. We formulate a nudging-based CDA system for the coupled NSCH--auxiliary-field model, in which coarse measurements are incorporated through a general linear observation operator. The observation mechanism is described abstractly by an interpolant satisfying an $H^{2}$-type approximation property, which is compatible with coarse spatial observations obtained from mesh coarsening and reconstruction. At the continuous level, we record two structural properties of the model: a formal energy law for the reference system and an evolution law for the phase mean in the assimilated dynamics. At the discrete level, we introduce a capped fully discrete finite element splitting scheme using continuous quadratic elements for the phase, chemical potential, velocity, and auxiliary field, together with continuous linear elements for the pressure. For this scheme, we prove one-step well-posedness and establish a stepwise a priori estimate for the capped method. Numerical experiments illustrate the practical behavior of the proposed CDA approach. They demonstrate recovery from strongly mismatched initial conditions and show how synchronization depends on the observation resolution, boundary forcing, and feedback strength. A coarse-indistinguishability experiment further shows that identical coarse initial information may correspond to distinct fine-scale evolutions, while the assimilated dynamics select the trajectory determined by the supplied time-dependent observations.

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。

↑