NUMERICAL SIMULATIONS OF A 3-DIMENSIONAL NOZZLE, FROM INVISCID TO TURBULENT FLOWS

Two numerical methods, based on high order finite volume formulations and upwind schemes, are used to compute the two- and three-dimensional flow field in a transonic nozzle. The influence of numerical diffusiv ity, boundary treatment and mesh structure is explored for inviscid an d turbulent configurations First order computations provide significan tly different inviscid results. However, high order methods lead to si milar solutions. An explanation of the error generated through the sho ckwave is proposed in this case. The two-dimensional interaction of th e shock with the thin turbulent boundary layer developing on the bump wall is also presented. Good agreement between both approaches is obta ined considering the rapid thickening of the boundary layer due to the shock. Furthermore, the downstream velocity recovery is almost identi cal. Only slight discrepancies occur in the main flow, near the outer edge of the boundary layer. These seem to be related to the way the tu rbulence model deals with the free stream turbulence. Finally, prelimi nary three-dimensional unstructured turbulent results are presented an d discussed.