Computational Modeling of Diving-turn Maneuvers Using a Hybrid Methodology

A Hybrid Navier-Stokes Free-Wake Computational Fluid Dynamics (CFD) methodology, coupled with a multi-body dynamics analysis code, has been applied to the UH-60A rotor to study the loads developed during selected revolutions of a severe diving turn maneuvers, flight counters 11680 and 11679. Loosely coupled CFD/CSD simulations were performed for selected revolutions of 11680 and 11679 characterized by maximum blade structural and pitch-link loads. Time histories of sectional normal loads and pitching moments, blade structural loads, and pitch-link loads for these revs have been examined. Harmonic content of structural loads for a representative revolution are presented and discussed. Results indicate that the current methodology gives an accurate prediction of harmonics 1P-3P, but under-predicts harmonics 4P-6P.