Contrast structures and rotating stall in MHD flows.

On the basis of the suggested two-dimensional model the possibility of arising of non-stationary induction MHD flow in wide channels or channels of a ring cross-section is discovered. This secondary flow has the features of "rotating stall", which is an example of non-stationary contrast structure. The existing experimental data validate the possibility to observe this phenomenon, which may be treated as a new type of stability loss. The carried out linear analysis proved that at certain relation between the parameters the system had less stability factor as related to non-stationary perturbations. The calculated region of instability for homogeneous stationary flow turned to be wider than that obtained with the help of one-dimensional model. In particular, the stability of the stationary homogeneous flow may be lost at the descending part of the external characteristic. The first numerical results of the study on arising secondary stationary and non-stationary flows far from branching points are obtained.