Modulational stability of rotating-disk flow

The problem of modulational primary stability of rotating-disk boundary layer flow for stationary modes was studied by using the method of multiple scales. The system of equations for infinitesimal disturbances is solved by linear stability theory to determine the modulated solution which represents the time and azimuthal variations of the wave pattern. The solution for the amplitude of the most critical disturbance indicates that the disturbance spreads out as the flow time increases and grows exponentially at the center.