DENSITY INTRUSIONS WITH LARGE RELATIVE THICKNESS

Previous analyses of density intrusions indicate that only relatively thin intrusions are allowed, to satisfy a momentum balance at the curr ent head. These constraints can be relaxed somewhat by various modific ations to the basic theory, but are inconsistent with experimental obs ervations indicating that intrusions occupying nearly the entire flow depth can be produced. An alternative theory of density current propag ation does not possess these restrictions on intrusion layer thickness and provides a more satisfactory explanation of experimental observat ions. New experimental results are presented to corroborate this inter pretation.