Keulegan Legacy: Saline Wedges

A review of Keulegan's contributions and influence in the field of stratified flow is presented. Emphasis is placed on the mechanics of the saline wedge, a topic in which he was actively engaged in research for 40 years. Keulegan's early analysis and experimental findings on the saline wedge are contrasted with recent theory, experimental studies, and field applications. The major difference in the early and later studies is in defining the role of the Reynolds number in the linking of laboratory and field work. The paper concludes with an account of the phenomenon of "dead water" encountered by a ship traversing the two-layer, salt-fresh-water stratification in the mouth of the Orinoco River in Venezuela. In understanding this phenomenon, use is made of some stratified flow experiments performed by Ekman at the turn of the century.