Peculiarity of Mathematical Models

The numerical methodologies underlying the mathematical models are among the most recent and vary, according to the cases, from the finite differences, to the finite elements and the boundary-elements, to the methods of the linear and non linear programming. The different use of numerical methodologies results from the intent to apply, where possible, the most appropriate tool of calculation for the solution of real problems, that appear so different in their fundamental characters. For this purpose, in a number of cases CREA’s research department developed innovative numerical algorithms:

• SuperNet optimization model to design pressure networks, with the combined use of three different mathematical models, i.e. the numerical simulator of the net, the model for the determination of characteristic trajectories of flows and the model of linear programming;

• WatMan optimization model for the management of pressure networks with the combined use of two different mathematical models, i.e. the simulator of the net and the model of linear programming;

• FEHM two-dimensional hydrodynamic finite element model for bays and lagoons, with the two levels semimplicit method;

• FEDM two-dimensional dispersive finite element model for bays and lagoons, with the modified method of characteristics;
• modello unidimensionale idrodinamico nelle reti a deflusso superficiale con il metodo degli elementi finiti e delle caratteristiche modificato FlowNet;

• modello unidimensionale dispersivo nelle reti a deflusso superficiale con il metodo degli elementi finiti e delle caratteristiche modificato DisNet.

The proposed models, which are exclusive ownership of CREA, were proved to simulate hydrodynamic processes in a perfect match with empirical data and to allow for an incomparable saving of resources in optimization processes.

Peculiarity of the Graphic Interface

To manage the information about physical systems under review, Microstation PC, a leading program in the CAD sector, was used as a basis of development, and it was integrated by special procedures in order to facilitate, as much as possible, operations of data acquisition and interpretation of the results supplied by the models. The graphic interface also constitutes a complete geographical territorial system GIS, where individual graphic elements of the network are provided with attributes directly managed by the model, including also pointers to possible external databases, autonomously managed by the client.

In preparing the graphic preprocessor for the mathematical models the need to guarantee an easy dialogue operator-system was deemed essential, in order to easily intervene in the network data upgrade. Besides, the proposed packages are able to pick up information coming from measure instruments in network, with the purpose to allow the simulation of the system in real time under different operational conditions and to send the optimal management manoeuvres identified by the model to the operational control. Some of many original features that CREA’ research department introduced in its own graphic interface are the following:

• detailed representation of the plants’ schemes for aqueducts and sewerages in unitary scale;
• plant graphic element management by their straight and geographically referenced visualization on the territory;
• technology of “Reference Files” to manage in a selective way the remarkable bulk of information about the hydrodynamic systems and the territory, keeping very low the time of access and visualization;
• a single graphic environment for the preparation of input data for the various mathematical models, for result representation and for GIS management;
• independent database management (material, reference files, load conditions, etc.).