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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2014, Vol. 35 ›› Issue (9): 2426-2437.doi: 10.7527/S1000-6893.2013.0519

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Calculations on Aeroelastic Loads of Rotor with Advanced Blade-tip Based on CFD/CSD Coupling Method

WANG Junyi, ZHAO Qijun, XIAO Yu   

  1. National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2013-11-06 Revised:2014-01-13 Online:2014-09-25 Published:2014-01-22
  • Supported by:

    National Natural Science Foundation of China (11272150)

Abstract:

Computational structural dynamics (CSD) is introduced into rigid rotor computational fluid dynamics (CFD) to enhance the accuracy of the unsteady aeroelastic load analysis of a rotor, and a CFD/CSD coupling method suitable for the aeroelastic analysis of a rotor with an advanced blade-tip is developed. The Navier-Stokes/Euler equations are adopted as the governing equations, and moving-embedded grids are generated around the rotor in forward flight. In the flowfield analysis, a dual time-stepping algorithm is employed in temporal discretization, while Jameson's central scheme is adopted in spatial discretization and a B-L(Baldwin-Lomax) turbulence model is included. The blade motion analysis is conducted based on Hamilton's variational principle and moderate deflection beam theory, and a new beam element method with an arbitrary junction angle is established to improve the accuracy of dynamics analysis on the rotor with an advanced blade-tip. The blade grid is deformed using algebraic transformation strategy, and a CFD/CSD loose coupling method is developed with blade motions and rotor airloads being transferred through the fluid-structure interface. The CSD and CFD modules are validated respectively, and the aeroelastic loads on a UH-60A rotor in high speed forward flight condition are calculated and compared with test data. Then, parametric investigations are carried out with emphasis on blade-tip shapes. The calculated results indicate that the present CFD/CSD method is able to improve the prediction accuracy of unsteady aeroelastic loads on the rotor as compared with the lifting-line method and rigid rotor CFD method, and the aeroelastic coupling effect of the rotor with the advanced blade-tip can be analyzed more precisely. Meanwhile, it is shown that a swept blade-tip shape can reduce the strength of shock at the advancing side between 30° and 90° azimuth angles, resulting in improved aerodynamic characteristics of the rotor.

Key words: rotor, aeroelastic load, advanced blade-tip, computational fluid dynamics, computational structural dynamics, loose coupling

CLC Number: