Rotor Loads Prediction on the ONERA 7A Rotor Using Loose Fluid/Structure Coupling

This work exploits the ONERA 7A rotor wind tunnel test for comparison with concurrent simulations at the U.S. Army and ONERA. Rotor airloads and structural loads are predicted by coupling computational fluid dynamics (CFD) with rotorcraft comprehensive analysis (CA). Two test points are examined: a high-speed point and a high-thrust point featuring dynamic stall. The contributions of experimental data processing and wind tunnel test stand to improved agreement are shown. Comparisons are shown for airloads, structural loads, surface pressures, rotor controls, and power. The use of state-of-theart CFD/CA coupled tools provides dramatic improvements in agreement with experiment, compared to previous work. The Helios/RCAS coupling used by the U.S. Army has been validated on the 7A rotor, adding to prior published validations on the UH-60A and HART-II rotors. The elsA/HOST (Helicopter Overall Simulation Tool) coupling used by ONERA has had its latest developments validated as well.