针对直升机野外作训作战复杂沙尘起降实际问题，通过精细化构建旋翼近地面干扰流场，计入沙粒DEM模型和Hertz-Mindlin沙粒碰撞力模型，构建直升机近地面扬沙综合建模分析方法。采用UH-60A标模旋翼验证了本文耦合流场及扬沙特性仿真可靠性。在此基础上，开展基于直升机近地面扬沙抑制的旋翼参数设计研究，通过对比不同方案的桨尖涡强度以及地面射流速度，结合流场-扬沙特性，分析桨尖下反角和先进三维桨尖（类BERP外形）对扬沙抑制的影响。结果表明：减小桨尖下反角，增加桨尖涡强度的同时可以提高地面射流速度，增大沙迹线外扩半径，提高沙尘环境可视度；
相比于抛物线桨尖，类BERP桨叶较强的桨尖涡与地面冲击后，同样可增大地面射流强度和速度，对地面沙尘扬起有较好的抑制效果，以此改善驾驶员的安全飞行视野范围。
In view of the practical problems of complex sand and dust take-off and landing in helicopter field training operations, a comprehensive modeling and analysis method for near-ground sand blowing of helicopters is established by finely constructing the rotor near-ground interference flow field and including it into the sand DEM model and Hertz-Mindlin sand collision force model. UH-60A standard rotor is used to verify the simulation reliability of coupled flow field and sand blowing characteristics in this paper. On this basis, the rotor parameter design research based on helicopter near-ground sand blowing suppression is carried out. By comparing the vortex intensity of blade tip and ground jet velocity in different schemes, combined with the flow field-sand blowing characteristics, the influence of blade tip dihedral angle and advanced three-dimensional blade tip (BERP-like shape) on sand blowing suppression is analyzed. The results show that: Reducing the lower diagonal angle of blade tip, increasing the vortex intensity at blade tip can improve the ground jet velocity, increase the outward expansion radius of sand track line and improve the visibility of dust environment.; Compared with parabolic blade tip, the strong tip vortex of BERP-like blade can also increase the intensity and velocity of ground jet after impacting with the ground, which has a better suppression effect on the rise of sand and dust on the ground, thus improving the pilot's safe flight vision range.
[1] POLZIN J W, GUNTUPALLI K， RAJAGOPALAN R G, Discrete blade model for rotorcraft brownout[C]//29th AIAA Applied Aerodynamic Conference. Reston, VA:AIAA,2011.
[2] SYAL M, LEISHMAN J G, Modeling of bombardment ejections in the rotorcraft brownout problem[J]. AIAA Journal, 2013,51(4):849-866
[3] SYAL M, LEISHMAN J G, Comparisons of predicted brownout dust clouds with photogrammetry measurements[C]//67th Annual Forum of the American Helicopter Society,2011.
[4] WONG O D,TANNER P E. photogrammetric measurements of an EH-60L brownout cloud[C]//American Helicopter Society 66th Annual Forum Proceedings,2010.
[5] 谭剑锋, 闫羽泽, 张卫国, 等. 沙盲环境直升机桨叶磨损分析方法[J]. 航空学报，2025,46(14):431012. TAN J F, YAN Y Z, ZHANG W G, et al. Analyzed method of helicopter balde erosion in brownout condition[J]. Acta Aeronantica et Astronautica Sinica,2025,46(14):431012（in Chinese）. doi. 10.7527/S1000-6893.2024.31012.
[6] OZEN I, GEDIKLI H, OZTURK B. Improvement of solid particle erosion resistance of helicopter rotor balde with hybrid composite shield[J].Engineering Failure Analysis,2021,121:105175.
[7] Acquisition and Technology Programs Task Force(ATPTF). Department of defense aviation safety technologies report[R]. Washington, D. C.: Defense Safety Oversight Council, Office of the Under Secretary of Defense for Personnel and Readiness,2009:22-23.
[8] BROWER M. Preventing brownout[J]. Special Operations Technology, 2004,2(4):1.
[9] 张卫国,谭剑锋,刘亚奎,等. 直升机“沙盲”现象研究进展[J].实验流体力学,2023,37(5):56-75.
ZHANG W G, TAN J F, LIU Y K，et al. Advances on helicopter brownout[J]. Journal of Experiments in Fluid Mechanincs, 2023,37(5):56-75.
[10] LEE T E, LEISHAMAN J G,RAMASAMY M. Fluid
dynamics of interacting balde tip vortices with a ground plane[J]. Journal of the American Helicopter Society, 2010, 55(2):022005.
[11] 胡建平,徐国华,史勇杰,等.基于CFD-DEM耦合数值模拟的全尺寸直升机沙盲形成机理[J].航空学报，2020,41(3):154-168.
[12] TAN J F, SUN Y M, BARAKOS G N. Vortex approach for downwash and outwash of tandem rotors in ground effect[J]. Journal of Aircraft,2018, 55(6):2491-2509.
[13] 谭剑锋,周天熠,王畅,等. 旋翼地面效应的气动建模与特性[J].航空学报,2019,40(6):106-116.
TAN J F, ZHOU T Y, WANG C, et al. Aerodynamic model and characteristics of rotor in ground effect[J]. Acta Aeronautica et Astronanutica Sinica, 2019,40(6):106-116.
[14] NATHAN N D. The rotor wake in ground effect and its investigation in a wind tunnel[D]. Scotland, UK: University of Glasgow, 2010.
[15] NATHAN N D, GREEN R B. Measurements of a rotor flow in ground effect and visualization of the brown-out phenomenon[C]//Proc of the 64th Annual Forum of the American Helicopter Society. 2008.
[16] 谭剑锋,何龙,于领军,等. 基于黏性涡粒子/沙粒DEM的直升机沙盲建模[J].航空学报，2022,43(8):351-361.
TAN J F,HE L,YU L J,et al.Helicopter brownout modeling based on visious vortex particle and sand particle DEM[J]. Acta Aeronautica et Astronautica Sinica, 2022,43(8):351-361.
[17] BRADLEY J, LEISHMAN J G, SYDNEY A, et al.Investigation of sediment entrainment in brownout using high-speed particle iamge velocimetry[C]//Proc of the 65th Annual Forum of the American Helicopter Society.2009.
[18] SYDNEY A, BAHARANI A, KEISHMAN J G. Understanding brownout using near-wall dual-phase flow measurements[C]//Proc of the 67th Annual Forum of the American Helicopter Society.2013.
[19] WHITEHOUSE G R, WACHSPRESS D A, QUACKENBUSH T R. Aerodynamic design of helicopter rotors for reduced brownout[C]//Proc of the Vertical Flight Society’s 76th Annual Forum & Technology Display,2020.doi:10.4050/f-0076-2020-16390.
[20] MILLUZZO J I, LEISHAMAN J G. Vortical sheet behavior in the wake of a rotor in ground effect[J]. AIAA Journal, 2016,55(1):24.
[21] SLADE K. Sharp new blades improve sea kings[R/OL]. UK Ministry of Defense. 2008.
[22] 谭剑锋,韩水,王畅，等. 基于DEM的直升机沙盲加速计算方法[J]. 北京航空航天大学学报, 2023,49(6):1352-1361.
TAN J F, HAN S, WANG C, et al. Accelerated computational method of helicopter brownout based on DEM[J]. Journal of Beijing University of Aeronautics and Astronautics, 2023,49(6):1352-1361(in Chinese).
[23] 朱明勇,招启军,王博. 基于CFD和混合配平算法的直升机旋翼地面效应模拟[J]. 航空学报，2016,37(8):2539-2551.
ZHU M Y, ZHAO Q J, WANG B. Simulation of helicopter rotor in ground effect based on CFD method and hybrid trim algorithm[J]. Acta Aeronantica et Astronautica Sinica, 2016,37(8):2539-2551.
[24] Menter F Zonal two equation kw turbulence models for aerodynamic flows[C]//23rd fluid dynamics,plasmadynamics,and lasers conference.1993:2906.
[25] Catalano P, Amato M. An evaluation of RANS turbulence modeling for aerodynamic application[J]. Aerospace science and Technolody.2003,7(7):493-509.
[26] KUTZ B M, KOWARSCH U, KEBLER M, et al. Numerical investigation of helicopter rotprs in ground effect[C]//30th AIAA Applied Aerodynamics Conference. Reston, VA:AIAA,2012.
[27] LEE T E, LEISHAMAN J G, RAMASAMY M. Fluid dynamics of interacting blade tip vortices with a ground plane[J]. Journal of the American Helicopter Society, 2010,55(2):22005-2200516.
CJA