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In this article, we study the gas expansion problem by turning a sharp corner into vacuum for the two-dimensional pseudo-steady compressible Euler equations with a convex equation of state. This problem can be considered as interaction of a…

Analysis of PDEs · Mathematics 2023-03-22 Rahul Barthwal , T. Raja Sekhar

We consider in this contribution a simplified idealized one-dimensional model in a nuclear core reactor coupling the diffusion equation on the neutron flux withthe enthalpy equation for the water which collects the heat produced by this…

Numerical Analysis · Mathematics 2025-03-11 Olivier Lafitte , François Dubois

The properties of LRS class II perfect fluid space-times are analyzed using the description of geometries in terms of the Riemann tensor and a finite number of its covariant derivatives. In this manner it is straightforward to obtain the…

General Relativity and Quantum Cosmology · Physics 2009-10-31 M. Marklund , M. Bradley

Typical fully conservative discretizations of the Euler compressible single or multi-component fluid equations governed by a real-fluid equation of state exhibit spurious pressure oscillations due to the nonlinearity of the thermodynamic…

Computational Physics · Physics 2025-12-05 Christopher DeGrendele , Nguyen Ly , Francois Cadieux , Michael Barad , Dongwook Lee , Jared Duensing

We present a general and practical procedure to solve the general relativistic hydrodynamic equations by using any of the special relativistic Riemann solvers recently developed for describing the evolution of special relativistic flows.…

Astrophysics · Physics 2007-05-23 Jose A. Pons , Jose A. Font , Jose M. Ibanez , Jose M. Marti , Juan A. Miralles

We present a numerical model for uniformly rotating superfluid neutron stars, for the first time with realistic microphysics including entrainment, in a fully general relativistic framework. We compute stationary and axisymmetric…

High Energy Astrophysical Phenomena · Physics 2016-11-04 Aurélien Sourie , Micaela Oertel , Jérôme Novak

Flows in rivers can be strongly affected by obstacles to flow or artificial structures such as bridges, weirs and dams. This is especially true during floods, where significant backwater effects or diversion of flow out of bank can result.…

Fluid Dynamics · Physics 2022-07-08 J. Mckenna , V. Glenis , C. Kilsby

We prove an existence result for the steady state flow of gas mixtures on networks. The basis of the model are the physical principles of the isothermal Euler equation, coupling conditions for the flow and pressure, and the mixing of…

Analysis of PDEs · Mathematics 2024-11-07 Alena Ulke , Michael Schuster , Simone Göttlich

An approximate Riemann solver for the equations of relativistic magnetohydrodynamics (RMHD) is derived. The HLLC solver, originally developed by Toro, Spruce and Spears, generalizes the algorithm described in a previous paper (Mignone &…

Astrophysics · Physics 2009-11-11 A. Mignone , G. Bodo

The objective of this paper is to apply the well-known exact operational matrices (EOMs) idea for solving the Emden-Fowler equations, illustrating the superiority of EOMs versus ordinary operational matrices (OOMs). Up to now, a few studies…

Numerical Analysis · Computer Science 2014-01-03 K. Parand , Sayyed A. Hossayni , J. A. Rad

Stochastic interpolants offer a robust framework for continuously transforming samples between arbitrary data distributions, holding significant promise for generative modeling. Despite their potential, rigorous finite-time convergence…

Machine Learning · Computer Science 2025-08-12 Yuhao Liu , Rui Hu , Yu Chen , Longbo Huang

We introduce a new class of numerical methods for solving McKean-Vlasov stochastic differential equations, which are relevant in the context of distribution-dependent or mean-field models, under super-linear growth conditions for both the…

Numerical Analysis · Mathematics 2025-02-10 Jiamin Jian , Qingshuo Song , Xiaojie Wang , Zhongqiang Zhang , Yuying Zhao

There is introduced a class of barotropic equations of state (EOS) which become polytropic of index $n = 5$ at low pressure. One then studies asymptotically flat solutions of the static Einstein equations coupled to perfect fluids having…

General Relativity and Quantum Cosmology · Physics 2009-10-31 R. Beig , M. Karadi

We ask the following question: Of the exact solutions to Einstein's equations extant in the literature, how many could represent the field associated with an isolated static spherically symmetric perfect fluid source? The candidate…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. S. R. Delgaty , Kayll Lake

Beginning with a special form of the Einstein-Rosen metric, we find new cosmological solutions of the Einstein equations, having two hypersurface-orthogonal Killing vectors , with ideal fluid. The equation of state is in the most cases of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 D. Kamani , R. Mansouri

We derive the soliton matrices corresponding to an arbitrary number of higher-order normal zeros for the matrix Riemann-Hilbert problem of arbitrary matrix dimension, thus giving the complete solution to the problem of higher-order…

Exactly Solvable and Integrable Systems · Physics 2009-11-10 V. S. Shchesnovich , J. Yang

We investigate the existence of analytic solutions for the field equations in the Einstein-\ae ther theory for a static spherically symmetric spacetime and provide a detailed dynamical system analysis of the field equations. In particular,…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Genly Leon , A. Coley , Andronikos Paliathanasis

A new Active Flux method for the multi-dimensional Euler equations is based on an additive operator splitting into acoustics and advection. The acoustic operator is solved in a locally linearized manner by using the exact evolution…

Numerical Analysis · Mathematics 2025-06-05 Wasilij Barsukow

This dissertation focuses on the reconstruction of Equations of State (EoSs) describing the interior of compact stars, using modern machine learning and deep learning methods. The pipeline is based on data from mass-radius (M-R) curves,…

Nuclear Theory · Physics 2025-09-17 Ioannis Stergakis

We discuss the procedure for the exact solution of the Riemann problem in special relativistic magnetohydrodynamics (MHD). We consider both initial states leading to a set of only three waves analogous to the ones in relativistic…

General Relativity and Quantum Cosmology · Physics 2009-11-11 B. Giacomazzo , L. Rezzolla