Variable-mesh difference equation for the stream function in axially symmetric flow

Finite Difference Discretization with Variable Mesh of the Schrödinger Equation in a Variable Domain

Abstract. We consider a partial differential equation of Schrödinger type, known as the ‘parabolic’ approximation to the Helmholtz equation in the theory of sound propagation in an underwater, rangeand depth-dependent environment with a variable bottom. We solve an associated initialand boundary-value problem by a finite difference scheme of Crank-Nicolson type on a variable mesh. We prove that...

A double layer potentials for generalized bi-axially symmetric equation

were constructed in R 2 = {(x, y) : x > 0, y > 0} . In the present paper (in case of λ = 0) using the constructed fundamental solutions, a double layer potentials are defined and investigated. Limiting theorems are proved, and integral equations concerning a denseness of potentials of a double layer are found. MSC: Primary 35J15, 35J70.

Variable Time Steps in the Solution of the Heat Flow Equation by a Difference Equation

Acoustic horizons for axially and spherically symmetric fluid flow

We investigate the formation of acoustic horizons for an inviscid fluid moving in a pipe in the case of stationary and axi-symmetric flow. We show that, differently from what is generally believed, the acoustic horizon forms in correspondence of either a local minimum or maximum of the flux tube cross-section. Similarly, the external potential is required to have either a maximum or a minimum a...

Quasi-axially symmetric stellarators.

Confinement of a plasma for controlled thermonuclear fusion is studied numerically. Toroidal equilibria are considered, with an emphasis on the Modular Helias-like Heliac 2 (MHH2), which is a stellarator of low aspect ratio with just two field periods surrounded by 16 modular coils. The geometry is fully three-dimensional, but there is an axial symmetry of the magnetic structure that is calcula...