Behrouz Emamizadeh

Variational problem for vortices attached to seamounts

Abstract The existence of an energy maximizer relative to a class of rearrangements of a given function is proved. The maximizers are stationary and stable solutions of the two-dimensional barotropic vorticity equation, governing the evolution of geophysical flow over a surface of variable height. The theorem proved implies the existence of a family of stable vortices with anticyclonic potential vorticity over a seamount, and a similar family of vortices with cyclonic potential vorticity over a localized depression.

Optimization problems for an elastic plate

This paper concerns optimization problems related to bi-harmonic equations subject to either Navier or Dirichlet homogeneous boundary conditions. Physically, in dimension two, our equation models the deformation of an elastic plate which is either hinged or clamped along the boundary, under load. We discuss existence, uniqueness, and properties of the optimizers.

STEADY VORTEX FLOWS OBTAINED FROM AN INVERSE PROBLEM

In this paper we prove the existence of solutions to an inverse semilinear elliptic partial differential equation. Physically, solutions represent stream functions of steady planar flows with bounded vortices. The kinetic energy functional is maximised over the set of rearrangements of a given function.

Monotonicity of the principal eigenvalue of the

In this note we prove a monotonicity result related to the principal eigenvalue of the p-Laplacian in an annulus in R N .

p

Ω ρ|u| dx. for all u ∈ W (Ω) were studied. In particular CF was characterized as the principal eigenvalue of an eigenvalue problem for the p-Laplacian with Robin boundary conditions. See sections 6 and 7 of ([2]). Here our interest is in the dependence of the constant CF on the boundary integral term in (1.1). Specifically we shall describe the behaviour of CF (s) on [0,∞) where CF (s) is the optimal constant in

-Laplacian in an annulus

This article is concerned with three optimization problems. In the first problem, a functional is maximized with respect to a set that is the weak closure of a rearrangement class; that is, a set comprising rearrangements of a prescribed function. Questions regarding existence, uniqueness, symmetry, and local minimizers are addressed. The second problem is of maximization type related to a Poisson boundary value problem. After defining a relevant function, we prove it is differentiable and derive an explicit formula for its derivative. Further, using the co-area formula, we establish a free boundary result. The third problem is the minimization version of the second problem.

Dependence of Friedrichs' constant on boundary integrals

In this note we introduce a variational problem with respect to an integrable fuzzy set f. The energy functional is maximized over a deleted σ-algebra. Using the decreasing rearrangement of f we prove that the admissible set can be replaced by the more convenient set of cuts of f. Finally an special case is considered where the variational problem can be transformed into a one dimensional setting.

Rearrangement Optimization Problems with Free Boundary

In this paper we will study a feature of a localised topographic flow. We will prove existence of an ideal fluid containing a bounded vortex, approaching a uniform flow at infinity and passing over a localised seamount. The domain of the fluid is the upper half-plane and the data prescribed is the rearrangement class of the vorticity field.

Decreasing rearrangement and a fuzzy variational problem

We prove the existence of steady two-dimensional ideal vortex flows occupying the first quadrant and containing a bounded vortex; this is done by solving a constrained variational problem. Kinetic energy is maximized subject to the vorticity, being a rearrangement of a prescribed function and subject to a linear constraint.

EXISTENCE OF SEAMOUNT STEADY VORTEX FLOWS

We study the problem of optimal harvesting of a marine species in a bounded domain, with the aim of minimizing harm to the species, under the general assumption that the fishing boats have different capacities. This is a generalization of a result of Kurata and Shi, in which the boats were assumed to have the same maximum harvesting capacity. For this generalization, we need a completely different approach. As such, we use the theory of rearrangements of functions. We prove existence of solutions, and obtain an optimality condition which indicates that the more aggressive harvesting must be pushed toward the boundary of the domain. Furthermore, we prove that radial and Steiner symmetries of the domain are preserved by the solutions. We will also devise an algorithm for numerical solution of the problem, and present the results of some numerical experiments.