To start a simulation in unsteady-state conditions from the edition mode of a scenario, just click on the button. This can also be done from the Project Explorer by selecting the scenario line and clicking the " Transient Calculation" button. Before the calculation, the software proposes to save the modifications made and performs consistency tests.

The coherence tests are currently designed for steady-state, if the boundary conditions and direction of flow do not correspond to those accepted in steady-state, these warnings should be disregarded.

During its implementation, the unsteady-state calculation program (SIRENE) will:

• Calculate the water line at each time step and record, at the frequency defined in time parameters, the results requested in calculation parameters > Writing Results
• Display on the screen the warnings and errors being calculated