Axisymmetric intrusions in two-layer and uniformly stratified environments with and without rotation

Abstract

Lock-release laboratory experiments have been performed to examine the collapse of a localized cylindrical mixed patch of fluid in both two-layer and uniformly stratified ambients. The experiments were performed with and without rotation. Unlike bottom propagating gravity currents, non-rotating intrusions typically propagated many lock radii at constant speed, sometimes stopping abruptly due to interactions with internal waves generated by the return flow into the lock. The initial front speeds of the resulting approximately axisymmetric intrusions emanating from locks of comparable depth and radius were found to be 30%–35% less than the predictions of rectilinear theory. Rotation had no impact on the intrusion's initial speed. However, it limited the maximum distance propagated by the intrusion and caused the patch to expand and contract as it approached geostrophic balance.