Experimental Validation of Tilt-Rotor Aerodynamic Predictions

A comparison of experimental data with several numerical predictions of the aerodynamic loads on the ERICA model is presented. The calculations are carried out by several Partners of the NICETRIP consortium, with different codes, turbulence models and grids, with the objective of validating the predictive capability of the CFD tools. Concerning the highly loaded minimum speed aircraft mode AC1, a large separation on the wings has been shown, both by experimental measurements and CFD simulations. Despite this large separation, a good agreement has been obtained between CFD simulations and wind tunnel measurements. Strong aerodynamic interactions between the 4/rev. blades passage and the tiltable wing, the nacelle and the fixed wing loads have been confirmed. Finally, we recommend increasing the aircraft speed flight and reducing the angle of attack for this configuration in order to avoid flow separation and reduce aircraft vibrations. In the highly loaded conversion mode CC4, a good agreement between CFD and experimental results has also been shown, in addition to 4/rev. loads fluctuations leading to aircraft vibrations.