Nearfield Performance of River Diffusers

The flowfield induced by a submerged multiport diffuser discharging across part of the width of a river is considered. A mathematical model is formulated for the flow in the nearfield region of a diffuser plume centered in a rectangular channel. The model is used to determine nearfield dilution as a function of effluent and ambient flow parameters. A family of dilution curves is presented for a range of conditions characteristic of prototype river diffusers. A method is given for applying the mathematical model to diffuser-induced flowfields in rivers. The model is also compared with measurements made in the Mississippi River downstream from the Quad Cities Nuclear Power Station diffuser.