Locating Discharge Trajectories in Still and Moving Ambient Fluids

The angular momentum principle is employed to locate the trajectories of wastewater plumes. This momentum-based method differs from the traditional approach where a perturbation analysis, based on the centerline velocities, is employed for locating discharges. Evidence of the latter can be found in existing Eulerian-integral and length-scale models. The momentumbased method is incorporated into the hybrid model SD3D, where the regional flow solutions are modified to incorporate the influences of relatively small components of momentum on the discharge trajectory. This method provides a clear understanding of the factors that influence the location of the discharge. The momentum-based approach yields analytical trajectory solutions in many cases, and it eliminates the need to arbitrarily select the appropriate characteristic velocity for locating the flow. Comparisons are made with available experimental data, and they show that the momentum-based method provides accurate predictions of the flow trajectories under a variety of discharge conditions. Comparisons are also made with predictions from the CORMIX1 and JETLAG models. In general the predictions are consistent, but some important discrepancies are highlighted. The use of the momentum-based method for locating discharges is discussed in light of recent experimental studies.