Junction Flow: Numerical scheme Assessment and Grid Convergence Study

The predictive capabilities of a structured and an unstructured code, both solving the incompressible RANS equations by means of the artificial compressibility formulation, are contrasted by reference to a complex three-dimensional flow past a wing-body junction for which detailed experimental data are available through the ERCOFTAC database. The structured code adopts a finite volume (FV), cell-centered formulation while the unstructured code uses residual distribution (RD) schemes and a vertex centered storage of the unknowns. The use of common grids, boundary conditions and turbulence model allows to draw conclutions on the relative performances of the two formulations, structured FV vs. unstructured RD, with respect to issues such as: computational efficiency, order of convergence, accuracy on coarse meshes. To this end, the GCI index proposed by Roache is used as a quantitative measure.