Integral boundary conditions for unsteady biomedical CFD applications
Résumé
A methodology to prescribe integral boundary conditions is proposed. The approach makes use of the decomposition of the solution into waves. It applies to any numerical method solving hyperbolic equations, including the compressible Navier-Stokes equations or their incompressible counterpart when solved through an artificial compressibility method. For any physical quantity to be imposed (e.g. the mass flow rate entering the computational domain), the boundary treatment consists in imposing a ID incoming 'acoustic' wave proportional to the difference between the mean quantity of interest (e.g. the mean mass flow rate) over the boundary and its prescribed target value. The approach is validated by computing both steady and pulsated channel flows for Womersley number upto 15. Results from a 3D simulation of the blood flow within a human aortic arch are briefly discussed.