Displaying 201 – 220 of 287

Showing per page

An inverse problem for the equation u = - c u - d

Michael Vogelius (1994)

Annales de l'institut Fourier

Let Ω be a bounded, convex planar domain whose boundary has a not too degenerate curvature. In this paper we provide partial answers to an identification question associated with the boundary value problem u = - c u - d in Ω , u = 0 on Ω . We prove two results: 1) If Ω is not a ball and if one considers only solutions with - c u - d 0 , then there exist at most finitely many pairs of coefficients ( c , d ) so that the normal derivative u ν | Ω equals a given ψ 0 .2) If one imposes no sign condition on the solutions but one additionally supposes that Ω is sufficiently...

An upper bound on the attractor dimension of a 2D turbulent shear flow with a free boundary condition

Mahdi Boukrouche, Grzegorz Łukaszewicz (2005)

Banach Center Publications

We consider a free boundary problem of a two-dimensional Navier-Stokes shear flow. There exist a unique global in time solution of the considered problem as well as the global attractor for the associated semigroup. As in [1] and [2], we estimate from above the dimension of the attractor in terms of given data and the geometry of the domain of the flow. This research is motivated by a free boundary problem from lubrication theory where the domain of the flow is usually very thin and the roughness...

Análisis de las singularidades de una ecuación diferencial fraccionaria no lineal.

Luis Vázquez (2005)

RACSAM

Se exponen las estimaciones numéricas preliminares de las singularidades de una ecuación diferencial fraccionaria no lineal. Dicha ecuación aparece en el estudio de las ondas viajeras asociadas a una ecuación de ondas que es una interpolación entre la ecuación de ondas clásica y la ecuación de Benjamin-Ono.

Analysis of Hamilton-Jacobi-Bellman equations arising in stochastic singular control

Ryan Hynd (2013)

ESAIM: Control, Optimisation and Calculus of Variations

We study the partial differential equation         max{Lu − f, H(Du)} = 0 where u is the unknown function, L is a second-order elliptic operator, f is a given smooth function and H is a convex function. This is a model equation for Hamilton-Jacobi-Bellman equations arising in stochastic singular control. We establish the existence of a unique viscosity solution of the Dirichlet problem that has a Hölder continuous gradient. We also show that if H is uniformly convex, the gradient of this solution...

Analysis of the boundary symbol for the two-phase Navier-Stokes equations with surface tension

Jan Prüss, Gieri Simonett (2009)

Banach Center Publications

The two-phase free boundary value problem for the Navier-Stokes system is considered in a situation where the initial interface is close to a halfplane. We extract the boundary symbol which is crucial for the dynamics of the free boundary and present an analysis of this symbol. Of particular interest are its singularities and zeros which lead to refined mapping properties of the corresponding operator.

Analysis of the free boundary for the p-parabolic variational problem (p ≥ 2).

Henrik Shahgholian (2003)

Revista Matemática Iberoamericana

Abstract Variational inequalities (free boundaries), governed by the p-parabolic equation (p > 2), are the objects of investigation in this paper. Using intrinsic scaling we establish the behavior of solutions near the free boundary. A consequence of this is that the time levels of the free boundary are porous (in N-dimension) and therefore its Hausdorff dimension is less than N. In particular the N-Lebesgue measure of the free boundary is zero for each t-level.

Currently displaying 201 – 220 of 287