Abstract
Efficiency of a prevention method on saline wedge intrusion in rivers using an air curtain (a two-dimensional bubble flow) was experimentally investigated from a viewpoint of a flow mechanism. The behavior of saline wedges in the presence of an air curtain is governed by the three external forces: the buoyancy of an air curtain A, the intrusion force of a saline wedge B and the inertial force of a fresh water flow R. It was found that the flow behavior could be classified into three types both by A/B dominating the rising discharge of salt water due to an air curtain, and by A/R dominating the strength (circulation) of a convection cell induced by an air curtain in its upstream side. In addition, the efficiency of this method was evaluated using the newly introduced parameter α through the discussion on the appearance conditions of the three flow types.
