HYBRID MODEL FOR PREDICTION OF INITIAL DILUTIONS FROM OUTFALL DISCHARGES

We present a model for predicting the behavior of a buoyant discharge in a cross-flow. The model is developed through a hybrid of the length scale and integral approaches. We compare the predictions of the hybr id model with a range of experimental data. In addition we compare the predictions of our model with those from two existing models: the exp ert system CORMIX1 and the Lagrangian integral model JETLAG. Through t hese comparisons we are able to show that the hybrid model predicts, w ith reasonable accuracy, the behavior of effluent discharged at a vari ety of angles to the ambient current. The hybrid model retains the fle xibility of a length-scale model enabling it to be developed more read ily to deal with complex flow configurations, such as the staged mergi ng of small groups of discharges. In addition because the model utiliz es integral solutions it requires less empirical information to develo p than an equivalent length-scale model, which relies solely on dimens ional analysis. Through this study we also are able to identify severa l areas of single-discharge behavior, which are not well understood an d require further investigation.