In this paper, the axisymmetric and non-axisymmetric buckling of finite elastic cylindrical shell, which is impacted on the end by axial step loads, is discussed with the aid of the stress wave propagating and reflecting. By solving the disturbed equations, the bifurcation condition of the dynamic buckling, critical buckling load and buckling mode are obtained. The results show that when the th...

Plasma balls and rings emerge as fluid holographic duals of black holes and black rings in the hydrodynamic/gravity correspondence for the Sherck-Schwarz AdS system. Recently, plasma balls spinning above a critical rotation were found to be unstable against m-lobed perturbations. In the phase diagram of stationary solutions the threshold of the instability signals a bifurcation to a new phase o...

We calculate the effect of a strong dipole magnetic field on non-axisymmetric oscillations for roAp stars, with a typical range of photospheric magnetic fields Bp [0.5-1.5] kG. As Dziembowski & Goode (1996), we find that the oscillations are strongly affected by such magnetic fields in two different ways. The first one concerns the stability of modes, which are damped due to dissipation by Alfv...

We present a perturbation theory for studying the instabilities of non-axisymmetric gaseous discs. We perturb the dynamical equations of self-gravitating fluids in the vicinity of a non-axisymmetric equilibrium, and expand the perturbed physical quantities in terms of a complete basis set and a small non-axisymmetry parameter ǫ. We then derive a linear eigenvalue problem in matrix form, and det...

In a recent important paper, Papaloizou & Pringle (1984) have investigated the dynamical stability of a thick, differentially rotating disc of uniform entropy and uniform specific angular momentum. They find a strong global non-axisymmetric instability which grows on a dynamical time-scale. Here we show that a similar instability exists even in thin discs of arbitrary specific angular momentum....

Abstract The problem of penetration an absolutely rigid round cone shaped indenter into a weighted rock (an axisymmetric plasticity problem) is being solved. Limit load, depending on the angle internal friction rock, adhesion, angular opening at top cone, weight, determined. dependence loading these parameters given.