The effect of a radial magnetic field on the stability of Couette flow through narrow-gap

The linear stability of Couette flow in a narrow-gap of two concentric cyli nders with either the inner one rotating or both counter-rotating, and in t he presence of a radial magnetic field is reported here. The eigenvalue pro blem is solved numerically by a finite-difference technique. The radial vel ocity perturbation and the cell-patterns at the onset of instability are sh own graphically. It is observed that the maximum of the radial velocity per turbation is found to shift increasingly towards the inner cylinder whereas the cells are found to elongate increasingly in the radial direction and g et reduced very much in the axial direction which is exactly opposite to th at observed in the presence of an axial magnetic field. Numerical values of the critical wave number a(c) and the critical Taylor number T-c are also listed.