This geometry is the F7/A7 contra rotating open rotor (CROR) tested in the NASA Lewis Wind Tunnel.
The objective of the project was to study both the aerodynamic and aeroacoustic behavior of the open rotor.
Thanks to the Non Linear Harmonic method implemented in the FINE™/Turbo CFD solver, the 3D unsteady flow field was obtained within affordable computational costs, meshing only one blade channel for each row.
The far field noise radiation of the configuration was evaluated by means of a free field acoustic propagation tool based on the Ffowcs Williams and Hawkings (FW-H) formulation.
The picture above features the configuration's high quality structured mesh.