Abstract
The long time motion of a linearly stratified inviscid non-diffusive fluid after the sudden discharge from a sink is studied theoretically. Both the line and the point sink flows are investigated. When the internal Froude number is small, the flow approaches the state of selective withdrawal. In this paper, we show in detail the asymptotic behaviour of internal waves which play an important role in establishing the selective withdrawal. Clear differences of the wave motion between the line and the point sink flows are also suggested.
