GRAVITY CURRENTS PRODUCED BY SUDDEN RELEASE OF A FIXED VOLUME OF HEAVY FLUID

In this paper we study various aspects of gravity (or density) current s arising from instantaneous releases of heavy fluids in a rectangular channel with a horizontal bottom. It is shown, by means of a scaling argument, that these plane currents can be successfully modeled by a t wo-by-two system in conservation form together with a pair of algebrai c relations. A number of numerical experiments are carried out using t his ''weak stratification'' model to elicit information concerning the behavior of gravity currents. A weakly nonlinear analysis is employed to clarify some aspects that were uncovered by the numerical experime ntation.