arXiv subjects

Vincent J. Ervin

Publications and source records attributed to Vincent J. Ervin.

4 recordsLinked to original sources

arXiv2019

A nonlinear Stokes-Biot model for the interaction of a non-Newtonian fluid with poroelastic media

We develop and analyze a model for the interaction of a quasi-Newtonian free fluid with a poroelastic medium. The flow in the fluid region is described by the nonlinear Stokes equations and in the poroelastic medium by the nonlinear quasi-static Biot model. Equilibrium and kinematic conditions are imposed on the interface. We establish existence and uniqueness of a solution to the weak formulation and its semidiscrete continuous-in-time finite element approximation. We present error analysis, complemented by numerical experiments.

math.NA↗

arXiv2015

DPG method with optimal test functions for a fractional advection diffusion equation

We develop an ultra-weak variational formulation of a fractional advection diffusion problem in one space dimension and prove its well-posedness. Based on this formulation, we define a DPG approximation with optimal test functions and show its quasi-optimal convergence. Numerical experiments confirm expected convergence properties, for uniform and adaptively refined meshes.

math.NA↗

arXiv1999

Escape Probability, Mean Residence Time and Geophysical Fluid Particle Dynamics

Stochastic dynamical systems arise as models for fluid particle motion in geophysical flows with random velocity fields. Escape probability (from a fluid domain) and mean residence time (in a fluid domain) quantify fluid transport between flow regimes of different characteristic motion. We consider a quasigeostrophic meandering jet model with random perturbations. This jet is parameterized by the parameter $β= (2Ω)/r \cos (θ)$, where $Ω$ is the rotation rate of the earth, $r$ the earth's radius and $θ$ the latitude. Note that $Ω$ and $r$ are fixed, so $β$ is a monotonic decreasing function of the latitude. The unperturbed jet (for $0 < β< 2/3$) consists of a basic flow with attached eddies. With random perturbations, there is fluid exchange between regimes of different characteristic motion. We quantify the exchange by escape probability and mean residence time.

math.DS↗

arXiv1998

Asymptotic Dynamical Difference between the Nonlocal and Local Swift-Hohenberg Models

In this paper the difference in the asymptotic dynamics between the nonlocal and local two-dimensional Swift-Hohenberg models is investigated. It is shown that the bounds for the dimensions of the global attractors for the nonlocal and local Swift-Hohenberg models differ by an absolute constant, which depends only on the Rayleigh number, and upper and lower bounds of the kernel of the nonlocal nonlinearity. Even when this kernel of the nonlocal operator is a constant function, the dimension bounds of the global attractors still differ by an absolute constant depending on the Rayleigh number.

math.DS↗