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We introduce an approximation technique for nonlinear hyperbolic systems with sources that is invariant domain preserving. The method is discretization-independent provided elementary symmetry and skew-symmetry properties are satisfied by…

Numerical Analysis · Mathematics 2019-01-30 Jean-Luc Guermond , Bojan Popov , Ignacio Tomas

A multi-scale method for the hyperbolic systems governing sediment transport in subcritical case is developed. The scale separation of this problem is due to the fact that the sediment transport is much slower than flow velocity. We first…

Numerical Analysis · Mathematics 2016-04-19 Yuchen Jiang , Ruo Li , Shuonan Wu

We present a new entropy-based moment method for the velocity discretization of kinetic equations. This method is based on a regularization of the optimization problem defining the original entropy-based moment method, and this gives the…

Numerical Analysis · Mathematics 2018-04-17 Graham W. Alldredge , Martin Frank , Cory D. Hauck

A new slender-body theory for viscous flow, based on the concepts of dimensional reduction and hyperviscous regularization, is presented. The geometry of flat, elongated, or point-like rigid bodies immersed in a viscous fluid is…

Fluid Dynamics · Physics 2016-03-23 Giulio G. Giusteri , Eliot Fried

Standard stochastic optimization methods are brittle, sensitive to stepsize choices and other algorithmic parameters, and they exhibit instability outside of well-behaved families of objectives. To address these challenges, we investigate…

Optimization and Control · Mathematics 2022-06-08 Hilal Asi , John C. Duchi

We introduce novel approximate systems for dispersive and diffusive-dispersive equations with nonlinear fluxes. For purely dispersive equations, we construct a first-order, strictly hyperbolic approximation. Local well-posedness of smooth…

Analysis of PDEs · Mathematics 2025-12-05 Rahul Barthwal , Firas Dhaouadi , Christian Rohde

The purpose of this paper is to derive rigorously the so called viscous shallow water equations given for instance page 958-959 in [A. Oron, S.H. Davis, S.G. Bankoff, Rev. Mod. Phys, 69 (1997), 931?980]. Such a system of equations is…

Analysis of PDEs · Mathematics 2016-11-27 Didier Bresch , Pascal Noble

We propose a variational framework for the resolution of a non-hydrostatic Saint-Venant type model with bottom topography. This model is a shallow water type approximation of the incompressible Euler system with free surface and slightly…

Numerical Analysis · Mathematics 2015-07-01 N. Aissiouene , M. -O. Bristeau , E. Godlewski , J. Sainte-Marie

Numerous codes are being developed to solve Shallow Water equations. Because there are used in hydraulic and environmental studies, their capability to simulate properly flow dynamics is critical to guarantee infrastructure and human…

The stability of Lattice Boltzmann Equations modelling Shallow Water Equations in the special case of reduced gravity is investigated theoretically. A stability notion is defined as applied in incompressible Navier-Stokes equations in…

Numerical Analysis · Mathematics 2016-10-06 Mapundi K. Banda , Tumelo R. A. Uoane

Numerical simulations are a valuable research and layout tool for fluid flow problems, yet repeated evaluations of parametrized problems, necessary to solve optimization problems, can be very costly. One option to speed up this process is…

Fluid Dynamics · Physics 2025-02-28 Marian Staggl , Wolfgang Sanz , Paul Pieringer

In this work we propose a novel method to ensure important entropy inequalities are satisfied semi-discretely when constructing reduced order models (ROMs) on nonlinear reduced manifolds. We are in particular interested in ROMs of systems…

Numerical Analysis · Mathematics 2024-07-18 Robin Klein , Benjamin Sanderse , Pedro Costa , Rene Pecnik , Ruud Henkes

We make a brief historical review to the moment model reduction to the kinetic equations, particularly the Grad's moment method for Boltzmann equation. The focus is on the hyperbolicity of the reduced model, which is essential to the…

Statistical Mechanics · Physics 2020-05-26 Zhenning Cai , Yuwei Fan , Ruo Li

The relativistic method of moments is one of the most successful approaches to extract second order viscous hydrodynamics from a kinetic underlying background. The equations can be systematically improved to higher order, and they have…

Nuclear Theory · Physics 2019-02-20 L Tinti , G Vujanovic , J Noronha , U Heinz

A formulation of the shallow water equations adapted to general complex terrains is proposed. Its derivation starts from the observation that the typical approach of depth integrating the Navier-Stokes equations along the direction of…

Fluid Dynamics · Physics 2018-10-17 Ilaria Fent , Mario Putti , Carlo Gregoretti , Stefano Lanzoni

This paper is dedicated to the study of both viscous compressible barotropic fluids and Navier-Stokes equation with dependent density, when the viscosity coefficients are variable, in dimension $d\geq2$. We aim at proving the local and…

Analysis of PDEs · Mathematics 2011-07-13 Frédéric Charve , Boris Haspot

We propose a novel method for fast and scalable evaluation of periodic solutions of systems of ordinary differential equations for a given set of parameter values and initial conditions. The equations governing the system dynamics are…

Dynamical Systems · Mathematics 2016-05-30 I. Yu. Tyukin , A. N. Gorban , T. A. Tyukina , J. Al Ameri , Yu. A. Korablev

The derivation of shallow water models from Navier-Stokes equations is revisited yielding a class of two-layer shallow water models.An improved velocity profile is proposed, based on the superposition of an ideal fluid and a viscous layer…

Analysis of PDEs · Mathematics 2018-06-11 François James , Pierre-Yves Lagrée , Hoang-Minh Le , Mathilde Legrand

Model reduction for fluid flow simulation continues to be of great interest across a number of scientific and engineering fields. Here, we explore the use of Neural Ordinary Differential Equations, a recently introduced family of…

Machine Learning · Computer Science 2021-04-30 Sourav Dutta , Peter Rivera-Casillas , Matthew W. Farthing

We propose a novel framework for model-order reduction of hyperbolic differential equations. The approach combines a relaxation formulation of the hyperbolic equations with a discretization using shifted base functions. Model-order…

Numerical Analysis · Mathematics 2021-05-03 Sara Grundel , Michael Herty