In questo lavoro si studia la instabilità gravitazionale di un fluido comprimibile, elettroconduttore, descritto dalle equazioni della magnetofluidodinamica in presenza delle correnti di Hall e di ion slip. Si determina la condizione per la instabilità relativa ad una classe di perturbazioni assialsimmetriche.
In this paper we extend to Plasma Mechanics the study of the hydrodynamic steady motions in which the streamlines are circular helixes. The plasma is described by the magnetofïuiddynamic equations with the Hall effect. Velocity and magnetic fields (and, in correspondence, the pressure field) that make such motions possible are determined. So a class of exact solutions of the magnetofïuiddynamic equations with the Hall effect is pointed out.
In according to a recent thermodynamic theory proposed by G. Grioli, we consider the growth of acceleration waves in a non viscous fluid. We determine the solutions for the growth of a plane or spherical wave advancing into the fluid in mechanical but not in thermal equilibrium.
In according to a recent thermodynamic theory proposed by G. Grioli we consider the growth of acceleration waves in a non viscous fluid. We determine the solutions for the growth of a plane or spherical wave advancing into the fluid in mechanical but not in thermal equilibrium.
Si dà un ulteriore contributo alla specificazione delle equazioni dinamiche di bilancio per una miscela di due fluidi non miscibili ma comprimibili.
This paper studies the magnetodynamic equilibrium of a radiative, infinitely conducting plasma, undergoing both a rotation motion around a symmetry axis and a motion in the meridian plans. It is assumed that on plasma acts its own gravitation. In the first nota the plasma is considered incompressible; for such a plasma the approximation of a perfect gas is valid.
This paper studies the magnetodynamic equilibrium of a radiative, infinitely conducting plasma, undergoing both a rotation motion around a symmetry axis and a motion in the meridian plans. It is assumed that on plasma acts its own gravitation. In the second note the plasma is supposed to be polytropic and compressible. The stability criterion of such a splasma is also obtained.
The development of velocity distribution in plane laminar flow is examined, neglecting inertial terms in respect to viscous ones. A solution is given, which satisfies all boundary conditions.
This paper presents a superconvergence result based on projection method for stabilized finite element approximation of the Stokes eigenvalue problem. The projection method is a postprocessing procedure that constructs a new approximation by using the least squares method. The paper complements the work of Li et al. (2012), which establishes the superconvergence result of the Stokes equations by the stabilized finite element method. Moreover, numerical tests confirm the theoretical analysis.