ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Calculations on Aeroelastic Loads of Rotor with Advanced Blade-tip Based on CFD/CSD Coupling Method
Received date: 2013-11-06
Revised date: 2014-01-13
Online published: 2014-01-22
Supported by
National Natural Science Foundation of China (11272150)
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.
WANG Junyi , ZHAO Qijun , XIAO Yu . Calculations on Aeroelastic Loads of Rotor with Advanced Blade-tip Based on CFD/CSD Coupling Method[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2014 , 35(9) : 2426 -2437 . DOI: 10.7527/S1000-6893.2013.0519
[1] Conlisk A T. Modern helicopter rotor aerodynamics[J]. Progress in Aerospace Science, 2001, 37(5): 419-476.
[2] Datta A, Chopra I. Prediction of the UH-60A main rotor structural loads using computational fluid dynamics/comprehensive analysis coupling[J]. Journal of the American Helicopter Society, 2008, 53(4): 351-365.
[3] Wang S C, Xu G H. Progress of helicopter rotor aerodynamics[J]. Journal of Nanjing University of Aeronautics and Astronautics, 2001, 33(3): 203-211. (in Chinese) 王适存, 徐国华. 直升机旋翼空气动力学的发展[J]. 南京航空航天大学学报, 2001, 33(3): 203-211.
[4] Brocklehurst A, Barakos G N. A review of helicopter rotor blade tip shapes[J]. Progress in Aerospace Sciences, 2013, 56: 35-74.
[5] Tung C, Caradonna F X, Johnson W. The prediction of transonic flows on an advancing rotor[J]. Journal of the American Helicopter Society, 1986, 32(7): 4-9.
[6] Potsdam M, Yeo H, Johnson W. Rotor airloads prediction using loose aerodynamic/structural coupling[J]. Journal of Aircraft, 2006, 43(5): 732-742.
[7] Ahmad J U, Chaderjian N M. High-order accurate CFD/CSD simulation of the UH-60 rotor in forward flight, AIAA-2011-3186[R]. Reston: AIAA, 2011.
[8] Wang H. Numerical simulation for the flowfield of new-tip rotors with effect of blade elasticity[D]. Nanjing: Nanjing University of Aeronautics and Astronautics, 2010. (in Chinese) 王海. 计入桨叶结构弹性的新型桨尖旋翼流场数值模拟研究[D]. 南京: 南京航空航天大学, 2010.
[9] Xiao Y, Xu G H, Shi Y J. Analysis of rotor airloads based on CFD/CA loose coupling[C]//Proceedings of the 2nd Annual Forum of the Asian/Australian Rotorcraft Forum and the 4th International Basic Research Conference on Rotorcraft Technology, 2013: 429-438.
[10] Datta A, Sitaraman J, Chopra I, et al. CFD/CSD prediction of rotor vibratory loads in high-speed flight[J]. Journal of Aircraft, 2006, 43(6): 1698-1709.
[11] Bousman W G. Aerodynamic characteristics of SC1095 and SC1094R8 airfoils, NASA TP-2003-212265[R].Washington, D. C.: NASA, 2003.
[12] Wang B, Zhao Q J, Xu G, et al. A new moving-embedded grid method for numerical simulation of unsteady flowfield of the helicopter rotor in forward flight[J]. Acta Aerodynamica Sinica, 2012, 30(1): 14-21. (in Chinese) 王博, 招启军, 徐广, 等. 一种适合于旋翼前飞非定常流场计算的新型运动嵌套网格方法[J]. 空气动力学学报, 2012, 30(1): 14-21.
[13] Meakin R L. A new method for establishing intergrid communication among systems of overs grids, AIAA-1991-1586[R]. Reston: AIAA, 1991.
[14] Xu G, Zhao Q J, Wang B, et al. Prediction on aerodynamic performance of advanced helicopter rotor in hover[J]. Acta Aeronautica et Astronautica Sinica, 2010, 31(9): 1723-1732. (in Chinese) 徐广, 招启军, 王博, 等. 先进直升机旋翼悬停状态气动性能计算[J]. 航空学报, 2010, 31(9): 1723-1732.
[15] Yuan K, Friedmann P. Aeroelasticity and structural optimization of composite helicopter rotor blades with swept tips, NASA CR-4665[R]. Washington, D. C.: NASA, 1995.
[16] Panda B. Assembly of moderate-rotation finite elements used in helicopter rotor dynamics[J]. Journal of the American Helicopter Society, 1987, 32(4): 63-69.
[17] Xie L, Xu M, An X M, et al. Research of mesh deforming method based on radial basis function and nonlinear aeroelastic simulation[J]. Acta Aeronautica et Astronautica Sinica, 2013, 34(7): 1501-1511. (in Chinese) 谢亮, 徐敏, 安效民, 等. 基于径向基函数的网格变形及非线性气动弹性时域仿真研究[J]. 航空学报, 2013, 34(7): 1501-1511.
[18] Xu M, An X M, Chen S L. CFD/CSD coupling numerical computational methodology[J]. Acta Aeronautica et Astronautica Sinica, 2006, 27(1): 33-37. (in Chinese) 徐敏, 安效民, 陈士橹. 一种CFD/CSD耦合计算方法[J]. 航空学报, 2006, 27(1): 33-37.
[19] Hopkins A S, Ormiston R A. An examination of selected problems in rotor blade structural mechanics and dynamics[C]//Proceedings of the 59th Annual Forum of the American Helicopter Society, 2003: 104-119.
[20] Davis S J. Predesign study for a modern 4-bladed rotor for the RSRA, NASA CR-166155[R]. Washington, D. C.: NASA, 1981.
[21] Hamade K S, Kufeld R M. Modal analysis of UH-60A instrumented rotor blades, NASA TM-4239[R]. Washington, D. C.: NASA, 1990.
[22] Pomin H, Wagner S. Navier-Stokes analysis of helicopter rotor aerodynamics in hover and forward flight[J]. Journal of Aircraft, 2002, 39(5): 813-821.
[23] Zhao Q J, Xu G H. Effects of swept blade tip on flowfield and aerodynamic characteristics of rotor[J]. Journal of Nanjing University of Aeronautics and Astronautics, 2012, 44(5): 706-712. (in Chinese) 招启军, 徐国华. 桨尖后掠对旋翼流场和气动特性的影响[J]. 南京航空航天大学学报, 2012, 44(5): 706-712.
/
| 〈 |
|
〉 |
CJA