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The block structure of double saddle-point problems has prompted extensive research into efficient preconditioners. This paper introduces a novel class of three-by-three block preconditioners tailored for such systems from the…

Numerical Analysis · Mathematics 2025-12-09 Achraf Badahmane

Neumann series underlie both Krylov methods and algebraic multigrid smoothers. A low-synch modified Gram-Schmidt (MGS)-GMRES algorithm is described that employs a Neumann series to accelerate the projection step. A corollary to the backward…

Numerical Analysis · Mathematics 2021-12-30 Stephen Thomas , Arielle Carr , Paul Mullowney , Ruipeng Li , Kasia Świrydowicz

Predictive simulation of many complex flows requires moving beyond Reynolds-averaged Navier-Stokes (RANS) based models to representations resolving at least some scales of turbulence in at least some regions of the flow. To resolve…

Fluid Dynamics · Physics 2018-12-11 Sigfried Haering , Todd A. Oliver , Robert D. Moser

In this work we exploit agglomeration based $h$-multigrid preconditioners to speed-up the iterative solution of discontinuous Galerkin discretizations of the Stokes and Navier-Stokes equations. As a distinctive feature $h$-coarsened mesh…

Computational Physics · Physics 2017-09-13 Lorenzo Botti , Alessandro Colombo , Francesco Bassi

Many subsurface engineering applications involve tight-coupling between fluid flow, solid deformation, fracturing, and similar processes. To better understand the complex interplay of different governing equations, and therefore design…

This article investigates matrix-free higher-order discontinuous Galerkin discretizations of the Navier--Stokes equations for incompressible flows with variable viscosity. The viscosity field may be prescribed analytically or governed by a…

Computational Engineering, Finance, and Science · Computer Science 2025-11-04 Richard Schussnig , Niklas Fehn , Douglas Ramalho Queiroz Pacheco , Martin Kronbichler

Novel fully discrete schemes are developed to numerically approximate a semilinear stochastic wave equation driven by additive space-time white noise. Spectral Galerkin method is proposed for the spatial discretization, and exponential time…

Numerical Analysis · Mathematics 2020-08-10 Xiaojie Wang , Siqing Gan , Jingtian Tang

We carry out a stability and convergence analysis of a fully discrete scheme for the time-dependent Navier-Stokes equations resulting from combining an $H(\mathrm{div}, \Omega)$-conforming discontinuous Galerkin spatial discretization, and…

Numerical Analysis · Mathematics 2025-10-22 L. Beirão da Veiga , F. Dassi , S. Gómez

We consider here a cell-centered finite difference approximation of the Richards equation in three dimensions, averaging for interface values the hydraulic conductivity $K=K(p)$, a highly nonlinear function, by arithmetic, upstream, and…

Numerical Analysis · Mathematics 2022-07-18 Daniele Bertaccini , Pasqua D'Ambra , Fabio Durastante , Salvatore Filippone

This study focuses on the numerical simulation of high Reynolds number separated flows and proposes a data-driven approach to improve the predictive capability of the SA turbulence model. First, data assimilation was performed on two…

Fluid Dynamics · Physics 2025-03-13 Xuxiang Sun , Xianglin Shan , Yilang Liu , Weiwei Zhang

Augmented Lagrangian preconditioners have successfully yielded Reynolds-robust preconditioners for the stationary incompressible Navier-Stokes equations, but only for specific discretizations. The discretizations for which these…

Numerical Analysis · Mathematics 2021-07-07 Patrick E. Farrell , Lawrence Mitchell , L. Ridgway Scott , Florian Wechsung

The paper compares standard iterative methods for solving the generalized Stokes problem arising from the time and space approximation of the time-dependent incompressible Navier-Stokes equations. Various preconditioning techniques are…

Numerical Analysis · Mathematics 2025-01-14 Melvin Creff , Jean-Luc Guermond

Recently, Garcke et al.[Garcke, Hinze, Kahle, A stable and linear time discretization for a thermodynamically consistent model for two-phase incompressible flow, Applied Numerical Mathematics 99, pp. 151-171, 2016] developed a consistent…

Numerical Analysis · Mathematics 2017-02-16 Jessica Bosch , Christian Kahle , Martin Stoll

This paper investigates the competitiveness of semi-implicit Runge-Kutta (RK) and spectral deferred correction (SDC) time-integration methods up to order six for incompressible Navier-Stokes problems in conjunction with a high-order…

Numerical Analysis · Mathematics 2022-10-03 Montadhar Guesmi , Martina Grotteschi , Jörg Stiller

This study proposes an algorithm for modeling compressible flows in spherical shells in nearly incompressible and weakly compressible regimes based on an implicit direction splitting approach. The method retains theoretically expected…

Numerical Analysis · Mathematics 2021-04-21 Roman Frolov , Peter Minev , Aziz Takhirov

Efficient frequency-domain Full Waveform Inversion (FWI) of long-offset node data can be designed with a few discrete frequencies hence allowing for compact volume of data to be managed. Moreover, attenuation effects can be…

Analysis of PDEs · Mathematics 2021-10-29 P. -H. Tournier , P. Jolivet , V. Dolean , H. S. Aghamiry , S. Operto , S. Riffo

Fully implicit tensor-product space-time discretizations of time-dependent $(p,\delta)$-Navier-Stokes models yield, on each time step, large nonlinear monolithic saddle-point systems. In the shear-thinning regime $1<p<2$, especially as…

Numerical Analysis · Mathematics 2026-03-31 Nils Margenberg , Carolin Mehlmann

We present a high order one-step ADER-WENO finite volume scheme with space-time adaptive mesh refinement (AMR) for the solution of the special relativistic hydrodynamic and magnetohydrodynamic equations. By adopting a local discontinuous…

High Energy Astrophysical Phenomena · Physics 2014-11-21 Olindo Zanotti , Michael Dumbser

Adaptive mesh refinement (AMR) in the high-order spectral-element method code Nek5000 is demonstrated and validated with well-resolved large-eddy simulations (LES) of the flow past a wing profile. In the present work, the flow around a NACA…

Fluid Dynamics · Physics 2021-08-30 F. Mallor , Á. Tanarro , N. Offermans , A. Peplinski , R. Vinuesa , P. Schlatter

The Residual Smooting Scheme (RSS) have been introduced in \cite{AverbuchCohenIsraeli} as a backward Euler's method with a simplified implicit part for the solution of parabolic problems. RSS have stability properties comparable to those of…

Numerical Analysis · Mathematics 2015-06-24 Brachet Matthieu , Chehab Jean-Paul