Correlation of helicopter rotor aeroelastic response with HART-II wind tunnel test data

摘要

Purpose - This paper aims to validate a comprehensive aeroelastic analysis for a helicopter rotor with the higher harmonic control aeroacoustic rotor testrn(HART-II) wind tunnel test data.rnDesign/methodology/approach - Aeroelastic analysis of helicopter rotor with elastic blades based on finite element method in space and time andrncapable of considering higher harmonic control inputs is carried out. Moderate deflection and coriolis nonlinearities are included in the analysis. The rotorrnaerodynamics are represented using free wake and unsteady aerodynamic models.rnFindings - Good correlation between analysis and HART-II wind tunnel test data is obtained for blade natural frequencies across a range of rotatingrnspeeds. The basic physics of the blade mode shapes are also well captured. In particular, the fundamental flap, lag and torsion modes compare very well.rnThe blade response compares well with HART-II result and other high-fidelity aeroelastic code predictions for flap and torsion mode. For the lead-lagrnresponse, the present analysis prediction is somewhat better than other aeroelastic analyses.rnResearch limitations/implications - Predicted blade response trend with higher harmonic pitch control agreed well with the wind tunnel test data, butrnusually contained a constant offset in the mean values of lead-lag and elastic torsion response. Improvements in the modeling of the aerodynamicrnenvironment around the rotor can help reduce this gap between the experimental and numerical results.rnPractical implications - Correlation of predicted aeroelastic response with wind tunnel test data is a vital step towards validating any helicopterrnaeroelastic analysis. Such efforts lend confidence in using the numerical analysis to understand the actual physical behavior of the helicopterrnsystem. Also, validated numerical analyses can take the place of time-consuming and expensive wind tunnel tests during the initial stage of the designrnprocess.rnOriginality/value - While the basic physics appears to be well captured by the aeroelastic analysis, there is need for improvement in the aerodynamicrnmodeling which appears to be the source of the gap between numerical predictions and HART-II wind tunnel experiments.