[en] Short communication

[en] We consider the basic issues of incompressible fluid dynamical equations. (open problem)

[en] The equations of hydrodynamics for an ideal incompressible fluid are solved to give a simply connected Possby vortex (solitary wave) that would develop in zonal plane flow with velocity shear. The resulting solution is qualitatively consistent with the properties of the Great Red Spot on Jupiter

[en] Isotropic and homogeneous cosmological models with a perfect fluid source in Brans-Dicke theory are investigated from the point or view of dynamical systems theory. (author)

[en] An investigation of the problem of stability of plane parallel flows in a magnetized plasma is presented, based on magnetohydrodynamics equations. The corresponding eigenvalue problem, for incompressible velocity perturbations, is solved numerically, by using continuous profiles for both plasma density and velocity at equilibrium. (author)

[en] The motion of stars in phase space are defined by Hamiltons equations and the flow of points can therefore be considered imcompressible. This motion is treated as an isocirculational flow, i.e. a flow preserving circulation around arbitrary closed loops within the fluid. (H.W.). 7 refs

[en] In this paper, the stabilities of MHD rotational discontinuities are analyzed. The results show that the rotational discontinuities in an incompressible magnetofluid are not always stable with respect to infinitesimal perturbation. The instability condition in a special case is obtained. (author)

[en] A method of solving linear problems of the uniform motion of a vortex source in a multilayer fluid having an arbitrary finite number of layers is proposed. As an example, the problem of the motion of a vortex source of given intensity in a three-layer fluid is solved. Formulas for the complex velocities and hydrodynamic reactions are obtained

[en] The capillary instability of an annular liquid jet surrounding a solid cylinder is presented. A general dispersion equation is derived based on the linear-perturbation technique. The instability as well as stability characteristics of that model are identified analytically and confirmed numerically. The model is unstable only to the axisymmetric perturbation whose wavelengths are longer than the circumference of the liquid jet, while it is stable to all other perturbations. The maximum temporal amplification values prevailing on such a model are fairly lower than those of the full liquid jet. The thicker the solid cylinder, whether it is regular or irregular, the larger is its stabilizing effect

[en] In this paper, a model for the unstable mixing of n parallel or concentric incompressible fluid layers is proposed. The approach to constructing this model is pairwise, based on a known two incompressible fluid mixing model. The problem complexity increases significantly in going from two to three fluids, but the increase in complexity is relatively small thereafter. We present a detailed study of the n=3 problem, which displays all of the difficult modeling issues applicable to arbitrary n≥3 while still being reasonably tractable.