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Related papers: Perturbation theorems for Hele-Shaw flows and thei…

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We numerically study, under a Gowdy symmetry assumption, nonlinear perturbations of the decelerated FLRW fluid solutions to the Einstein-Euler system toward the future for linear equations of state $p=K\rho$ with $0\leq K\leq 1$. This…

General Relativity and Quantum Cosmology · Physics 2025-05-12 Elliot Marshall

Evolution of scalar perturbations in a universe containing solid matter with positive pressure is studied. Solution for pure solid is found and matched with solution for ideal fluid, including the case when the pressure to energy density…

General Relativity and Quantum Cosmology · Physics 2015-01-29 Vladimír Balek , Matej Škovran

We present new solutions to the strong explosion problem in a non power law density profi{}le. The unperturbed self similar solutions developed by Sedov, Taylor and Von Neumann describe strong Newtonian shocks propagating into a cold gas…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Almog Yalinewich , Re'em Sari

The first well founded perturbation theory for classical solid systems is presented. Theoretical approaches to thermodynamic and structural properties of the hard-sphere solid provide us with the reference system. The traditional…

Condensed Matter · Physics 2009-10-28 C. Rascon , L. Mederos , G. Navascues

We introduce a discrete numerical method based on the diffusion-limited aggregation (DLA) approach to simulate two-fluid Hele-Shaw flow subject to the Saffman-Taylor interfacial instability, in the case where the displaced fluid is…

Fluid Dynamics · Physics 2024-11-13 J. Adriazola , B. Gu , L. Cummings , L. Kondic

A new approach to study the scaling behavior of the scalar theory near the Gaussian fixed point in $d$-dimensions is presented. For a class of initial data an explicit use of the Green's function of the evolution equation is made. It is…

High Energy Physics - Theory · Physics 2009-10-31 Alfio Bonanno

This paper is motivated by the study of Lyapunov functionals for four equations describing free surface flows in fluid dynamics: the Hele-Shaw and Mullins-Sekerka equations together with their lubrication approximations, the Boussinesq and…

Analysis of PDEs · Mathematics 2020-04-08 Thomas Alazard , Didier Bresch

A Streamline Upwind Petrov-Galerkin (SUPG) finite element method for transient convection-diffusion-reaction equation in time-dependent domains is proposed. In particular, a convection dominated transient scalar problem is considered. The…

Numerical Analysis · Mathematics 2015-09-07 Sashikumaar Ganesan , Shweta Srivastava

We investigate the interplay between Horava-Lifshitz (HL) gravity and more general theories where the local Hamiltonian constraint is lost, for example due to the time variability of the Lagrangian (e.g. via its parameters) where time is…

General Relativity and Quantum Cosmology · Physics 2025-02-11 Paolo M Bassani , Joao Magueijo , Shinji Mukohyama

This paper investigates shear flow in a Hele-Shaw cell, driven by varying horizontal buoyancy forces resulting from a horizontal density gradient induced by a scalar field. By employing asymptotic methods and taking the dependence of…

Fluid Dynamics · Physics 2025-06-03 Prabakaran Rajamanickam

The onset of convection in a horizontal layer of fluid heated from below in the presence of a gravity field varying across the layer is investigated. The eigenvalue problem governing the linear stability of the mechanical equilibria of the…

Mathematical Physics · Physics 2007-09-17 Ioana Dragomirescu

We assess experimentally the scaling laws that characterize the mixing region produced by the Rayleigh-Taylor instability in a confined porous medium. In particular, we wish to assess experimentally the existence of a superlinear scaling…

Fluid Dynamics · Physics 2024-08-02 Marco De Paoli , Diego Perissutti , Cristian Marchioli , Alfredo Soldati

Reaction cross diffusion systems are a two species generalization of the porous media equation. These systems play an important role in the mechanical modeling of living tissues and tumor growth. Due to their mixed parabolic-hyperbolic…

Analysis of PDEs · Mathematics 2021-07-28 Matt Jacobs

Eulerian hydrodynamical simulations are a powerful and popular tool for modeling fluids in astrophysical systems. In this work, we critically examine recent claims that these methods violate Galilean invariance of the Euler equations. We…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-03 Brant E. Robertson , Andrey V. Kravtsov , Nickolay Y. Gnedin , Tom Abel , Douglas H. Rudd

The accurate numerical simulation of turbulent incompressible flows is a challenging topic in computational fluid dynamics. For discretisation methods to be robust in the under-resolved regime, mass conservation as well as energy stability…

Computational Physics · Physics 2025-10-20 Niklas Fehn , Martin Kronbichler , Christoph Lehrenfeld , Gert Lube , Philipp W. Schroeder

Local polarization effects, induced by mono and divalent positive ions in water, influence (and in turn are influenced by) the large scale structural properties of the solvent. Experiments can only distinguish this process of interplay in a…

Soft Condensed Matter · Physics 2007-07-04 Christian Krekeler , Luigi Delle Site

A large population limit of the parabolic-parabolic Patlak-Keller-Segel (PKS) system with degenerate, nonlinear diffusion, e.g., of porous medium-type $-\frac{m}{m-1}\mathrm{div}(\rho \nabla \rho^{m-1})$, is studied. We show,…

Analysis of PDEs · Mathematics 2025-10-21 Michael Rozowski

We construct a new Godunov type relativistic hydrodynamics code in Milne coordinates, using a Riemann solver based on the two-shock approximation which is stable under the existence of large shock waves. We check the correctness of the…

Nuclear Theory · Physics 2017-07-18 Kazuhisa Okamoto , Yukinao Akamatsu , Chiho Nonaka

We analyze the stability of stationary solutions of a singular Vlasov type hydrodynamic equation (HE). This equation was derived (under suitable assumptions) as the hydrodynamical scaling limit of the Hamiltonian evolution of a system…

Statistical Mechanics · Physics 2009-11-10 E. Caglioti , N. Chernov , J. L. Lebowitz

As an experimental model to mimic the flow of bio-fluids in the cell and the flow in tiny blood capillaries, we study the co-moving shear flow of dilute polymeric solutions. An inflection point shear flow profile is created by parallel…

Fluid Dynamics · Physics 2025-10-09 Jimreeves David M