Shallow Jets Research Articles

BOUNDARY EFFECTS ON A SUBMERGED JET GROUP

A vortex model is employed to calculate the flow induced by a line group of submerged high velocity shallow water jets discharging in proximity to a shoreline boundary. Based on an inviscid flow model, a kinematic and dynamic boundary condition are formulated along the unknown lines of velocity discontinuity downstream of the multiple jets. This results in two governing nonlinear integral equations in terms of the unknown circulation strength along the unknown slip streamlines. The numerically computed two dimensional momentum-induced flow shows that, as the jet group is placed closer to the boundary, the contraction of the slipstream becomes stronger, resulting in a decrease of the induced flow. All of the features predicted by the theory are in good agreement with experimental results of this and previous investigations.

Ageostrophic Stability of Divergent Jets

Abstract The barotropic stability of divergent jets is studied under the condition of small but nonzero Rossby number. Small disturbances to the basic state consist of fast waves of inertio-gravity type and slow waves with speeds comparable to those of the basic current. It is shown that the fast waves are stable and do not amplify. It is also shown, for a velocity profile resembling that of the Gulf Stream, that the slow waves are destabilized by ageostrophic effects in the sense that waves of fixed wavenumber which are neutral for zero Rossby number amplify for nonzero Rossby number. For very shallow jets it is found that the complex wave velocity is small and that disturbances will be neutrally stable unless the jet has a countercurrent.