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A fully discrete finite element method, based on a new weak formulation and a new time-stepping scheme, is proposed for the surface diffusion flow of closed curves in the two-dimensional plane. It is proved that the proposed method can…

Numerical Analysis · Mathematics 2021-07-28 Wei Jiang , Buyang Li

Surrogate strategies are used widely for uncertainty quantification of groundwater models in order to improve computational efficiency. However, their application to dynamic multiphase flow problems is hindered by the curse of…

Machine Learning · Statistics 2019-05-02 Shaoxing Mo , Yinhao Zhu , Nicholas Zabaras , Xiaoqing Shi , Jichun Wu

We consider a multicontinuum model in porous media applications, which is described as a system of coupled flow equations. The coupling between different continua depends on many factors and its modeling is important for porous media…

Probability · Mathematics 2020-01-27 Hakima Bessaih , Razvan Florian Maris

In this paper, we discuss multiscale methods for nonlinear problems. The main idea of these approaches is to use local constraints and solve problems in oversampled regions for constructing macroscopic equations. These techniques are…

Numerical Analysis · Mathematics 2019-04-01 Wing T. Leung , Eric T. Chung , Yalchin Efendiev , Mary F. Wheeler

This article presents a multi-physics methodology for the numerical simulation of physical systems that involve the non-linear interaction of multi-phase reactive fluids and elastoplastic solids, inducing high strain-rates and high…

Computational Physics · Physics 2021-06-04 Tim Wallis , Philip T. Barton , Nikolaos Nikiforakis

We present a new finite volume scheme for anisotropic heterogeneous diffusion problems on unstructured irregular grids, which simultaneously gives an approximation of the solution and of its gradient. In the case of simplicial meshes, the…

Numerical Analysis · Mathematics 2016-08-16 Jérôme Droniou , Robert Eymard

In this paper, we present a sparse grid-based Monte Carlo method for solving high-dimensional semi-linear nonlocal diffusion equations with volume constraints. The nonlocal model is governed by a class of semi-linear partial…

Numerical Analysis · Mathematics 2025-07-08 Changtao Sheng , Bihao Su , Chenglong Xu

Multiphase flows are characterized by sharp moving interfaces, separating different fluids or phases. In many cases the dynamics of the interface determines the behavior of the flow. In a coarse, or reduced order model, it may therefore be…

Fluid Dynamics · Physics 2021-08-12 Xianyang Chen , Jiacai Lu , Gretar Tryggvason

We present a method to downscale idealized geophysical fluid simulations using generative models based on diffusion maps. By analyzing the Fourier spectra of images drawn from different data distributions, we show how one can chain together…

Machine Learning · Computer Science 2023-05-04 Tobias Bischoff , Katherine Deck

Machine learning-based weather forecasting models now surpass state-of-the-art numerical weather prediction systems, but training and operating these models at high spatial resolution remains computationally expensive. We present a modular…

Machine Learning · Computer Science 2026-04-02 Aymeric Delefosse , Anastase Charantonis , Dominique Béréziat

Coarse-guided visual generation, which synthesizes fine visual samples from degraded or low-fidelity coarse references, is essential for various real-world applications. While training-based approaches are effective, they are inherently…

Computer Vision and Pattern Recognition · Computer Science 2026-03-31 Yanghao Wang , Ziqi Jiang , Zhen Wang , Long Chen

The diffuse medium in and around galaxies can exist in a multi-phase state: small, cold gas clouds contributing significantly to the total mass embedded in pressure equilibrium with a hotter, more diffuse volume-filling component. Modeling…

Astrophysics of Galaxies · Physics 2022-12-28 Rainer Weinberger , Lars Hernquist

We present a new way to construct analytical solutions for flow in complex microfluidic channel networks, as well as planar disordered media. Using a combination of Schwarz-Christoffel maps and segmentation techniques inspired by integrated…

Fluid Dynamics · Physics 2026-03-24 Etienne Boulais , Richard D. Braatz

Convergence failure and slow convergence rates are among the biggest challenges with solving the system of non-linear equations numerically. Although mitigated, such issues still linger when using strictly small time steps and…

Numerical Analysis · Mathematics 2019-12-05 Hanyu Li , Wing Tat Leung , Mary F. Wheeler

Many modern production and measurement facilities incorporate multiphase systems at low pressures. In this region of flows at small, non-zero Knudsen- and low Mach numbers the classical mesoscopic Monte Carlo methods become increasingly…

Fluid Dynamics · Physics 2015-09-10 S. Schmieschek , D. K. N. Sinz , F. Keller , U. Nieken , J. Harting

Real world networks are often subject to severe uncertainties which need to be addressed by any reliable prescriptive model. In the context of the maximum flow problem subject to arc failure, robust models have gained particular attention.…

Discrete Mathematics · Computer Science 2017-05-24 Fabian Mies , Britta Peis , Andreas Wierz

In this paper we develop a conservative sharp-interface method dedicated to simulating multiple compressible fluids. Numerical treatments for a cut cell shared by more than two materials are proposed. First, we simplify the interface…

Computational Physics · Physics 2019-05-30 Shucheng Pan , Luhui Han , Xiangyu Hu , Nikolaus. A. Adams

In this paper, we present an efficient numerical algorithm for solving the time-dependent Cahn--Hilliard--Navier--Stokes equations that model the flow of two phases with different densities. The pressure-correction step in the projection…

Numerical Analysis · Mathematics 2020-11-02 Chen Liu , Deep Ray , Christopher Thiele , Lu Lin , Beatrice Riviere

In this paper, we propose a deep-learning-based approach to a class of multiscale problems. THe Generalized Multiscale Finite Element Method (GMsFEM) has been proven successful as a model reduction technique of flow problems in…

Numerical Analysis · Mathematics 2018-10-30 Min Wang , Siu Wun Cheung , Eric T. Chung , Yalchin Efendiev , Wing Tat Leung , Yating Wang

The stochastic variational approach for geophysical fluid dynamics was introduced by Holm (Proc Roy Soc A, 2015) as a framework for deriving stochastic parameterisations for unresolved scales. This paper applies the variational stochastic…

Fluid Dynamics · Physics 2022-09-16 Colin Cotter , Dan Crisan , Darryl D. Holm , Wei Pan , Igor Shevchenko