Numerical modelling is an appropriate technique for the prediction of the performance of sediment control devices. The ability to overcome the scaling difficulties associated with laboratory models for this application, and cost considerations, make numerical modelling an attractive option for either supplementing or replacing physical models.

The report
The development of a numerical model for predicting flow patterns and sediment movement at intakes is presented. The model is based on a widely used software package which models fluid flow in three dimensions. The report describes how the package has been developed for the prediction of sediment exclusion at river intakes.

The approach used computational fluid dynamics (CFD) software to develop the numerical model. The CFD code "PHOENICS" was chosen for the study. This report presents the work to develop the model since 1989.

• The intake to the Agno River Irrigation system in Central Luzon, the Philippines
  
• The intake to the Kapunga Rice Project in southern Tanzania

The model results are compared to the field data and an assessment is made of the sensitivity of model predictions to the assumptions required to run the model and to uncertainties in the input data.

Conclusions and recommendations for further application of the model are presented. It was found that the model, as described in this report, is primarily suited to assess modifications to existing intakes rather than the design of new intakes.

Contributors
HR Wallingford Ltd, UK; National Irrigation Administration, Philippines; National Agricultural and Food Corporation, Tanzania.

Intended users
The report is aimed at design engineers familiar with computational fluid dynamics.

Atkinson, E, 1995. A numerical model for predicting sediment exclusion at intakes HR Wallingford, UK, Report no. OD 130.