In the present report an improved solution algorithm is described for the SIMRA program. The algorithm is a segregated, implicit projection method, which improves the stability property substantially. Although the computer demands increase per time step due to the new implicit formulation, the total gain is considerably because of a much better stability. An additional gain is the improved robustness, meaning that there are no needs for strong “safety” restrictions on the Courant number. The algorithm is described and analysed formally for properties like consistency, stability and accuracy. In addition the method is demonstrated on some test cases, including two- and three-dimensional cases, neutral and stratified flows.

Oppdragsgiver Avinor AS