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We propose a model for the coupling of flow and transport equations with porous membrane-type conditions on part of the boundary. The governing equations consist of the incompressible Navier--Stokes equations coupled with an…

Numerical Analysis · Mathematics 2025-10-07 Arbaz Khan , David Mora , Ricardo Ruíz-Baier , Jesus Vellojin

This paper contributes to the exploration of a recently introduced computational paradigm known as second-order flows, which are characterized by novel dissipative hyperbolic partial differential equations extending accelerated gradient…

Numerical Analysis · Mathematics 2025-05-13 Haifan Chen , Guozhi Dong , José A. Iglesias , Wei Liu , Ziqing Xie

This paper introduces an efficient second-order method for solving the elastic net problem. Its key innovation is a computationally efficient technique for injecting curvature information in the optimization process which admits a strong…

Optimization and Control · Mathematics 2019-01-25 Vien V. Mai , Mikael Johansson

State estimation in multi-layer turbulent flow fields with only a single layer of partial observation remains a challenging yet practically important task. Applications include inferring the state of the deep ocean by exploiting surface…

Fluid Dynamics · Physics 2025-09-30 Zhongrui Wang , Nan Chen , Di Qi

This article provides a reduced-order modelling framework for turbulent compressible flows discretized by the use of finite volume approaches. The basic idea behind this work is the construction of a reduced-order model capable of providing…

Fluid Dynamics · Physics 2024-05-31 Matteo Zancanaro , Valentin Nkana Ngan , Giovanni Stabile , Gianluigi Rozza

The potential for data-driven applications to scale-resolving simulations of turbulent flows is assessed herein. Multigrid sequential data assimilation algorithms have been used to calibrate solvers for Large Eddy Simulation for the…

In this paper, we present a novel second order in time mixed finite element scheme for the Cahn-Hilliard-Navier-Stokes equations with matched densities. The scheme combines a standard second order Crank-Nicholson method for the…

Numerical Analysis · Mathematics 2016-06-09 Amanda E. Diegel , Cheng Wang , Xiaoming Wang , Steven M. Wise

Aitken extrapolation normally applied to convergent fixed point iteration is extended to extrapolate the solution of a divergent iteration. In addition, higher order Aitken extrapolation is introduced that enables successive decomposition…

Numerical Analysis · Mathematics 2013-10-17 Ababu Teklemariam Tiruneh

We consider model order reduction based on proper orthogonal decomposition (POD) for unsteady incompressible Navier-Stokes problems, assuming that the snapshots are given by spatially adapted finite element solutions. We propose two…

Numerical Analysis · Mathematics 2019-08-02 Carmen Gräßle , Michael Hinze , Jens Lang , Sebastian Ullmann

This paper considers the backward Euler based linear time filtering method for the EMAC formulation of the incompressible Navier-Stokes equations. The time filtering is added as a modular step to the standard backward Euler code leading to…

Numerical Analysis · Mathematics 2022-03-11 Medine Demir , Aytekin Çıbık , Songül Kaya

We use high order finite difference methods to solve the wave equation in the second order form. The spatial discretization is performed by finite difference operators satisfying a summation-by-parts property. The focus of this work is on…

Numerical Analysis · Mathematics 2017-02-08 Siyang Wang , Kristoffer Virta , Gunilla Kreiss

We investigate theoretically and numerically the use of the Least-Squares Finite-element method (LSFEM) to approach data-assimilation problems for the steady-state, incompressible Navier-Stokes equations. Our LSFEM discretization is based…

Fluid Dynamics · Physics 2020-04-20 Alexander Schwarz , Richard Dwight

Data assimilation methodologies are designed to incorporate noisy observations of a physical system into an underlying model in order to infer the properties of the state of the system. Filters refer to a class of data assimilation…

Optimization and Control · Mathematics 2013-08-06 C. E. A. Brett , K. F. Lam , K. J. H. Law , D. S. McCormick , M. R. Scott , A. M. Stuart

Second-order methods for convex optimization outperform first-order methods in terms of theoretical iteration convergence, achieving rates up to $O(k^{-5})$ for highly-smooth functions. However, their practical performance and applications…

Optimization and Control · Mathematics 2024-10-15 Dmitry Kamzolov , Dmitry Pasechnyuk , Artem Agafonov , Alexander Gasnikov , Martin Takáč

In this paper, both semidiscrete and fully discrete finite element methods are analyzed for the penalized two-dimensional unsteady Navier-Stokes equations with nonsmooth initial data. First order backward Euler method is applied for the…

Numerical Analysis · Mathematics 2026-04-16 Bikram Bir , Deepjyoti Goswami , Amiya K. Pani

In this study we propose a-posteriori error estimation results to approximate the precision loss in quantities of interests computed using reduced order models. To generate the surrogate models we employ Proper Orthogonal Decomposition and…

Numerical Analysis · Mathematics 2024-12-20 R. Stefanescu , A. Sandu

In this study, we explore data assimilation for the Stochastic Camassa-Holm equation through the application of the particle filtering framework. Specifically, our approach integrates adaptive tempering, jittering, and nudging techniques to…

Numerical Analysis · Mathematics 2024-02-13 Colin John Cotter , Dan Crisan , Maneesh Kumar Singh

In this paper, we consider the back and forth nudging algorithm that has been introduced for data assimilation purposes. It consists of iteratively and alternately solving forward and backward in time the model equation, with a feedback…

Optimization and Control · Mathematics 2010-11-30 Didier Auroux , Maëlle Nodet

This paper develops a smoothing-based postprocessing method for superconvergence in finite element methods. The method applies a few smoothing iterations, such as damped Jacobi, Gauss-Seidel, or conjugate gradient, with initial guess being…

Numerical Analysis · Mathematics 2026-05-07 Yuwen Li , Han Shui , Ludmil Zikatanov

We prove optimal error bounds for a second order in time finite element approximation of curve shortening flow in possibly higher codimension. In addition, we introduce a second order in time method for curve diffusion. Both schemes are…

Numerical Analysis · Mathematics 2026-01-29 Klaus Deckelnick , Robert Nürnberg