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We derive boundary conditions at interfaces (contact discontinuities) for a class of Lagrangian models describing, in particular, bubbly flows. We use these conditions to study Kelvin-Helmholtz' instability which develops in the flow of two…

Fluid Dynamics · Physics 2008-01-17 Sergey L. Gavrilyuk , Henri Gouin , Vladimir M. Teshukov

In the present paper we consider convection and cracking instabilities as well as their interplay. We develop a simple criterion to identify equations of state unstable to convection, and explore the influence of buoyancy on cracking (or…

General Relativity and Quantum Cosmology · Physics 2018-11-14 Héctor Hernández , Luis A. Núñez , Adriana Vásquez-Ramírez

We explore analytically the structure of relativistic shock and solitary wave solutions in collisionless plasmas. In the wave frame of reference, a cold plasma is flowing from one end and impacting on a low velocity plasma. First we show…

Astrophysics · Physics 2007-05-23 David Medvigy , Abraham Loeb

We investigate existence, stability, and instability of anchored rotating spiral waves in a model for geometric curve evolution. We find existence in a parameter regime limiting on a purely eikonal curve evolution. We study stability and…

Pattern Formation and Solitons · Physics 2026-02-06 Anthony Cortez , Nan Li , Nathan Mihm , Alice Xu , Xiaoxing Yu , Arnd Scheel

The common feature of sheared flows of an ideal fluid and plasma in magnetic field is the Kelvin-Helmholtz instability. This instability is described by identical equations in mentioned two cases. The wave equation for the eigenmodes in the…

Plasma Physics · Physics 2012-07-31 A. Yu. Chirkov , V. I. Khvesyuk

The stability of solutions under periodic perturbations for both inviscid and viscous conservation laws is an interesting and important problem. In this paper, a large-amplitude viscous shock under space-periodic perturbation for the…

Analysis of PDEs · Mathematics 2021-09-15 Feimin Huang , Qian Yuan

Shocks in granular media, such as vertically oscillated beds, have been shown to develop instabilities. Similar jet formation has been observed in explosively dispersed granular media. Our previous work addressed this instability by…

Fluid Dynamics · Physics 2014-07-17 Nick Sirmas , Sam Falle , Matei Radulescu

Astrophysical discs which are sufficiently massive and cool are linearly unstable to the formation of axisymmetric structures. In practice, linearly stable discs of surface density slightly below the threshold needed for this instability…

Earth and Planetary Astrophysics · Physics 2025-01-22 Joshua J. Brown , Gordon I. Ogilvie

This paper is concerned with the asymptotic stabilities of the inviscid and viscous shocks for the scalar conservation laws on the half-line $(-\infty,0)$ with shock speed $s<0$, subjected to the time-periodic boundary condition, which…

Analysis of PDEs · Mathematics 2025-10-31 Yuan Yuan

We demonstrate with a minimal example that in Filippov systems (dynamical systems governed by discontinuous but piecewise smooth vector fields) stable periodic motion with sliding is not robust with respect to stable singular perturbations.…

Chaotic Dynamics · Physics 2010-07-13 Jan Sieber , Piotr Kowalczyk

We argue that self-excited instabilities are the cause of spiral patterns in simulations of unperturbed stellar discs. In previous papers, we have found that spiral patterns were caused by a few concurrent waves, which we claimed were…

Astrophysics of Galaxies · Physics 2019-08-14 J. A. Sellwood , Ray G. Carlberg

Continuing a line of investigation initiated by Texier and Zumbrun on dynamics of viscous shock and detonation waves, we show that a linearly unstable Lax-type viscous shock solution of a semilinear strictly parabolic system of conservation…

Analysis of PDEs · Mathematics 2008-11-10 Kevin Zumbrun

A new condition for the linear dissipative instability of the strong plane shock wave in an arbitrary medium is obtained. The instability of the shock is realized due to the flow instability behind its front, which is similar to the known…

Fluid Dynamics · Physics 2020-06-24 Sergey G. Chefranov

We consider the stability of periodic gravity free-surface water waves traveling downstream at a constant speed over a shear flow of finite depth. In case the free surface is flat, a sharp criterion of linear instability is established for…

Analysis of PDEs · Mathematics 2007-11-28 Vera Mikyoung Hur , Zhiwu Lin

Symmetry-breaking instability of a laterally uniform granular cluster (strip state) in a prototypical driven granular gas is investigated. The system consists of smooth hard disks in a two-dimensional box, colliding inelastically with each…

Soft Condensed Matter · Physics 2009-11-07 Evgeniy Khain , Baruch Meerson

It has been suggested that the wiggle instability (WI) of spiral shocks in a galactic disk is responsible for the formation of gaseous feathers observed in grand-design spiral galaxies. We perform both a linear stability analysis and…

Astrophysics of Galaxies · Physics 2015-08-19 Yonghwi Kim , Woong-Tae Kim , Bruce G. Elmegreen

When an upstream steady uniform supersonic flow impinges onto a symmetric straight-sided wedge, governed by the Euler equations, there are two possible steady oblique shock configurations if the wedge angle is less than the detachment angle…

Analysis of PDEs · Mathematics 2019-01-18 Gui-Qiang G. Chen

Superconducting cosmic string may admit shock-like discontinuities of the current when the latter is spacelike ("magnetic" regime), while no shock at timelike current ("electric" regime) was discovered in numerical simulations. We find that…

High Energy Physics - Theory · Physics 2016-01-28 Ernst Trojan , George V. Vlasov

We characterize the dynamical instability responsible for the breakdown of regular rows and necklaces of quantized vortices that appear at the interface between two superfluids in relative motion. Making use of a generalized point-vortex…

Quantum Gases · Physics 2024-09-12 Matteo Caldara , Andrea Richaud , Massimo Capone , Pietro Massignan

Spiral wave patterns observed in models of cardiac arrhythmias and chemical oscillations develop alternans and stationary line defects, which can both be thought of as period-doubling instabilities. These instabilities are observed on…

Dynamical Systems · Mathematics 2019-05-30 Stephanie Dodson , Bjorn Sandstede