It is well known that most PDE problems defined over an axisymmetric domain can be efficiently solved by a Fourier based solution method. However, for many applications, the underlying computational domain is not entirely axisymmetric, but has one or several major axisymmetric subdomains. For such problems, an axisymmetric analysis method is not applicable, and a straightforward one can be inef...

Increasing observations are becoming available about a relatively weak, but persistent, non-axisymmetric magnetic field co-existing with the dominant axisymmetric field on the Sun. It indicates that the non-axisymmetric magnetic field plays an important role in the origin of solar activity. A linear non-axisymmetric α − Ω dynamo model is set up to discuss the characteristics of the axisymmetric...

Observations show that solar activity is distributed non-axisymmetrically, concentrating at “preferred longitudes”. This indicates the important role of non-axisymmetric magnetic fields in the origin of solar activity. We investigate the generation of the non-axisymmetric fields and their coupling with axisymmetric solar magnetic field. Our kinematic generation (dynamo) model operating in a sph...

in this paper, an analytical study of the forced vibrations of hexapod table is studied. considering external force as a time sinusoid force, forced vibrations of the platform are investigated. resonance frequencies and vibrations of the moving platform are also calculated in different directions. the results of the analytical approach are verified using fem simulation. modelling the harmonic m...

Self-gravitating stellar disks with random motion support both exponentially growing and, in some cases, purely oscillatory axisymmetric bending modes, unlike their cold disk counterparts. A razor-thin disk with even a very small degree of random motion in the plane is both unstable and possesses a discrete spectrum of neutral modes, irrespective of the sharpness of the edge. Random motion norm...

The purpose of this study is to determine more accurately the marginal stability condition for axisymmetric waves since it is believed that an unstable axisymmetric wave could affect the amplification of spiral waves. An axisymmetric wave with a gradient term of velocity dispersion ( surface density ) is derived. Analysis of this axisymmetric wave with a gradient term for our own galaxy shows t...

Context. The MHD instabilities can generate complex field topologies even if the initial field configuration is a very simple one. Aims. We consider the stability properties of magnetic configurations containing a toroidal and an axial field. In this paper, we concentrate mainly on the behavior of non-axisymmetric perturbations in axisymmetric magnetic configurations. Methods. The stability is ...