Development of a Coupled Implicit Incompressible Flow Solver in CODA

The discretization of the incompressible Navier-Stokes equations leads to a saddle-point problem in which the discrete equations for the pressure and momentum are coupled. Traditionally, this coupling is handled by segregated methods in which separate equations for momentum and pressure are solved with the constraint of obtaining a divergence-free velocity field. In the fully coupled approach, a single block system of equations for the momentum and pressure is formulated and solved simultaneously. Furthermore, the solution of such a coupled system has been shown to improve robustness and convergence properties. In the present work, a coupled approach for the solution of the incompressible Navier-Stokes and RANS equations have been developed in the finite volume framework of the CFD software CODA (CFD for ONERA, DLR and AIRBUS). The implementation is verified and validated with various test cases.