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In this work, we study a fourth order exponential equation, $u_t=\Delta e^{-\Delta u},$ derived from thin film growth on crystal surface in multiple space dimensions. We use the gradient flow method in metric space to characterize the…

Analysis of PDEs · Mathematics 2022-11-08 Yuan Gao , Jian-Guo Liu , Xin Yang Lu

We present a geometric variational discretization of nonlinear elasticity in 2D and 3D in the Lagrangian description. A main step in our construction is the definition of discrete deformation gradients and discrete Cauchy-Green deformation…

Numerical Analysis · Mathematics 2022-10-19 François Demoures , François Gay-Balmaz

Over the past few years, we developed a mathematically rigorous method to study the dynamical processes associated to nonlinear Forchheimer flows for slightly compressible fluids. We have proved the existence of a geometric transformation…

Differential Geometry · Mathematics 2013-02-26 Eugenio Aulisa , Akif Ibragimov , Magdalena Toda

We formulate a perturbative approximation to gravitational instability, based on Lagrangian hydrodynamics in Newtonian cosmology. We take account of `pressure' effect of fluid, which is kinematically caused by velocity dispersion, to aim…

Astrophysics · Physics 2009-11-07 Masaaki Morita , Takayuki Tatekawa

Two-dimensional turbulent flows, and to some extent, geophysical flows, are systems with a large number of degrees of freedom, which, albeit fluctuating, exhibit some degree of organization: coherent structures emerge spontaneously at large…

Statistical Mechanics · Physics 2017-03-21 Corentin Herbert

It is investigated a possibility of physical interpretation of vector fields (dynamic flows) in Euclidean spaces of higher dimension. There are analyzed the methods of measurements of dynamic flows, the characteristics of dynamic flow and…

General Mathematics · Mathematics 2007-05-23 I. V. Bayak

The diffusion driven by the gradient of the chemical potential (by the Fick/Darcy law) in deforming continua at large strains is formulated in the reference configuration with both the Fick/Darcy law and the capillarity gradient term…

Analysis of PDEs · Mathematics 2019-04-02 Tomáš Roubíček

Lagrangian multiform theory is a variational framework for integrable systems. In this article we introduce a new formulation which is based on symplectic geometry and which treats position, momentum and time coordinates of a…

Mathematical Physics · Physics 2025-04-01 Vincent Caudrelier , Derek Harland

New aspects of turbulence are uncovered if one considers flow motion from the perspective of a fluid particle (known as the Lagrangian approach) rather than in terms of a velocity field (the Eulerian viewpoint). Using a new experimental…

Fluid Dynamics · Physics 2009-11-07 N. Mordant , J. Delour , E. Leveque , A. Arneodo , J. -F. Pinton

Theoretical description of liquids has been primarily based on the hydrodynamic approach and its generalization to the solid-like regime. We show that the same liquid properties can be derived starting from solid-like equations and…

Statistical Mechanics · Physics 2017-12-28 K. Trachenko

A new Lagrangian particle method for solving Euler equations for compressible inviscid fluid or gas flows is proposed. Similar to smoothed particle hydrodynamics (SPH), the method represents fluid cells with Lagrangian particles and is…

Numerical Analysis · Mathematics 2016-03-21 Hsin-Chiang Chen , Roman Samulyak , Wei Li

Turbulent fluid flows exhibit a complex small-scale structure with frequently occurring extreme velocity gradients. Particles probing such swirling and straining regions respond with an intricate shape-dependent orientational dynamics,…

Fluid Dynamics · Physics 2020-11-30 Leonhard A. Leppin , Michael Wilczek

In {\em{Holm}, Proc. Roy. Soc. A 471 (2015)} stochastic fluid equations were derived by employing a variational principle with an assumed stochastic Lagrangian particle dynamics. Here we show that the same stochastic Lagrangian dynamics…

Analysis of PDEs · Mathematics 2017-10-25 Colin J Cotter , Georg A Gottwald , Darryl D Holm

We present a new formalism which allows to derive the general Lagrangian dynamical equations for the motion of gravitating particles in a non--flat Friedmann universe with arbitrary density parameter $\Omega$ and no cosmological constant.…

Astrophysics · Physics 2015-06-24 Paolo Catelan

We have studied the gradient-flow equations in information geometry from a point-particle perspective. Based on the motion of a null (or light-like) particle in a curved space, we have rederived the Hamiltonians which describe the…

Mathematical Physics · Physics 2025-08-04 Tatsuaki Wada , Antonio M. Scarfone

There is growing evidence that the hydrodynamic gradient expansion is factorially divergent. We advocate for using Dingle's singulants as a way to gain analytic control over its large-order behaviour for nonlinear flows. Within our…

High Energy Physics - Theory · Physics 2022-11-01 Michal P. Heller , Alexandre Serantes , Michał Spaliński , Viktor Svensson , Benjamin Withers

In this paper, we exploit the gradient flow structure of continuous-time formulations of Bayesian inference in terms of their numerical time-stepping. We focus on two particular examples, namely, the continuous-time ensemble Kalman-Bucy…

Numerical Analysis · Mathematics 2019-06-24 Sahani Pathiraja , Sebastian Reich

Shape optimization based on surface gradients and the Hadarmard-form is considered for a compressible viscous fluid. Special attention is given to the difference between the 'function composition' approach involving local shape derivatives…

Optimization and Control · Mathematics 2013-12-23 Matthias Sonntag , Stephan Schmidt , Nicolas R. Gauger

We study the Lagrangian trajectories of statistically isotropic, homogeneous, and stationary divergence free spatiotemporal random vector fields. We design this advecting Eulerian velocity field such that it gets asymptotically rough and…

Fluid Dynamics · Physics 2020-07-08 Jason Reneuve , Laurent Chevillard

In this paper we are interested in geometric aspects of blowup in the axisymmetric 3D Euler equations with swirl on a cylinder. Writing the equations in Lagrangian form for the flow derivative along either the axis or the boundary and…

Analysis of PDEs · Mathematics 2016-03-23 Stephen C. Preston , Alejandro Sarria