High-Fidelity Structural Loads Analysis of the ONERA 7A Rotor

Abstract

The ONERA 7A rotor wind-tunnel test data are investigated to assess the accuracy of analytical tools in the calculation of rotor airloads and structural loads. Comprehensive analysis codes, HOST and RCAS, and coupled computational fluid dynamics/comprehensive analysis codes, elsA/HOST and Helios/RCAS, are used to examine the ONERA 7A rotor-blade dynamics, trim, airloads, and structural loads, and the calculated results are compared with the measured data for both high-speed and high-thrust conditions. The present elsA and Helios analyses include the test-stand modeling. Comprehensive analyses show significant phase differences for the airloads and structural loads. The phase correlation is substantially improved by the coupled analyses for both high-speed and high-thrust conditions. In general, the coupled analyses also improve the half peak-to-peak correlation of structural loads compared to the comprehensive analyses. The majority of the predictions from the coupled analyses in half peak-to-peak blade structural loads are within 20% of the measured data. The present study shows unprecedented correlation of structural loads for the 7A rotor, consistently better than the previous structural loads correlation for the UH-60A rotor using Helios/RCAS analysis.