The model of three-dimensional low-altitude windshear with turbulence is systematically established, its threat to helicopter flight safety is comprehensively analyzed. A windshear model composed of microburst and atmosphere turbulence is developed. Without increasing the amount of calculation, a helicopter flight dynamic model integrated with wind velocity and windshear items is proposed, which optimizes the simulation precision of helicopter dynamic response through the windshear. Then a flight control system with attitude holding is synthesized into this model to correspond to the general helicopter flight state and to improve the response performance of helicopter. Following this, based on the characteristics of the windfield model, various flight velocities and windfield positions are selected and analyzed their relation between state changes and windfield. From the aspect of dynamics, the formula of response is derived theoretically with the vertical channel as the example. The results show that the turbulence mainly induces high frequency attitude response, while the windshear plays a dominant role in flight state influence, and the vertical downwind is the main inducement of threat. Based on the results, suggestions to avoid the windfiled threat are proposed.
ZHAO Yanqin
,
CHEN Renliang
. Systematical modelling of low-altitude windshear and its qualitative threat analysis to helicopter flight safety[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2020
, 41(7)
: 123413
-123413
.
DOI: 10.7527/S1000-6893.2020.23413
[1] 肖业伦, 金长江. 大气扰动中的飞行原理[M]. 北京:国防工业出版社, 1993:166-173. XIAO Y L,JIN C J. Flight theory in atmosphere turbulence[M]. Beijing:National Defense Industry Press,1993:166-173(in Chinese).
[2] 高华. 风切变对直升机飞行特性的影响[D]. 南京:南京航空航天大学, 2009. GAO H. Research on helicopter flight characteristics in wind shear[D]. Nanjing:Nanjing University of Aeronautics and Astronautics, 2009(in Chinese).
[3] FAA. Windshear training aid. Volume 1. overview, pilot guide, training program[R]. Washington, D.C.:Federal Aviation Administration, 1987.
[4] IVAN M. A ring-vortex downburst model for flight simulations[J]. Journal of Aircraft, 1986, 23(3):232-236.
[5] 高振兴. 复杂大气扰动下大型飞机飞行实时仿真建模研究[D]. 南京:南京航空航天大学, 2009. GAO Z X. Research on real-time flight simulation of large aircraft in complex atmospheric disturbance[D]. Nanjing:Nanjing University of Aeronautics and Astronautics, 2009(in Chinese).
[6] MCFARLAND R E. Element simulation of helicopter turbulence:USA, 5860807[P]. 1999-01-09.
[7] 吉洪蕾, 陈仁良, 李攀. 适用于直升机飞行力学分析的三维空间大气紊流模型[J]. 航空学报, 2014, 35(7):1825-1835. JI H L,CHEN R L,LI P. A model of three dimension-al field atmospheric turbulence for helicopter flight dynamics analysis[J]. Acta Aeronautica et Astronautica Sinica,2014,35(7):1825-1835(in Chinese).
[8] FROST W, BOWLES R L. Wind shear terms in the equations of aircraft motion[J]. Journal of Aircraft, 1984, 21(11):866-872.
[9] BOWLES R L. Windshear detection and avoidance:Airborne systems survey[C]//29th IEEE Conference on Decision and Control. Piscataway:IEEE, 1990:708-736.
[10] PROCTOR F H, HINTON D A, BOWLES R L. A windshear hazard index[C]//9th Conference on Aviation, Range and Aerospace Meteorology. Orlando:American Meteorology Society, 2000:482-487.
[11] DOGAN A, KABAMBA P T. Escaping microburst with turbulence:Altitude, dive, and pitch guidance strategies[J]. Journal of Aircraft, 2000, 37(3):417-426.
[12] LIU T, DAI Y, HONG G. Flight dynamic simulation of helicopter forward flight through microburst wind field[J]. Advances in Mechanical Engineering, 2017, 9(2):168781401769121.
[13] 洪冠新, 庞健. 风切变场中直升机前飞状态动态响应[J]. 北京航空航天大学学报, 2005, 31(5):524-528. HONG G X, PANG J. Helicopter dynamic response to wind shear in forward flight[J]. Journal of Beijing University of Aeronautics and Astronautics, 2005, 31(5):524-528(in Chinese).
[14] 赵维义, 傅百先. 低空风切变中直升机纵向运动特性分析[J]. 飞行力学, 2002, 20(1):25-28. ZHAO W Y, FU B X. Analysis of the helicopter longitudinal motion characteristics in the low-level windshear[J]. Flight Dynamics, 2002, 20(1):25-28(in Chinese).
[15] ETKIN B. Turbulent wind and its effect on flight[J]. Journal of Aircraft, 1981, 18(5):327-345.
[16] HOWLETT J J. UH-60A Black Hawk Engineering Simulation Program:Volume I-mathematical model:NASA CR 166309[R]. Washington, D.C.:NASA, 1984.
[17] HOWLETT J J. UH-60A Black Hawk Engineering Simulation Program:Volume II-background report:NASA CR 166310[R]. Washington, D.C.:NASA, 1988.
[18] HILBERT K B. A mathematical model of the UH-60 Helicopter:NASA-TM-85890[R]. Washington, D.C.:NASA,1984.
[19] GAONKAR G, PETERS D. Review of dynamic inflow modeling for rotorcraft flight dynamics[C]//27th Structures, Structural Dynamics and Materials Conference, 1986.
[20] PETERS D A, HAQUANG N. Technical note:Dynamic inflow for practical applications[J]. Journal of the American Helicopter Society, 1988, 33(4):64-68.
[21] TALBOT P D, TINLING B E, DECKER W A, et al. A mathematical model of a single main rotor helicopter for piloted simulation:NASA TM-84281[R]. Washington, D.C.:NASA, 1982.
[22] BALLIN M G. Validation of a real-time engineering simulation of the UH-60A helicopter:NASA TM 88360[R]. Washington, D.C.:NASA, 1987.
[23] 黄子安, 韩智修, 朱家祯. 直升机三轴增稳改善风切变作用下的飞行品质[J]. 南京航空航天大学学报, 1996(3):98-103. HUANG Z A, HAN Z X, ZHU J Z. A three-axis stability augmentation system for improving helicopter flying qualities under effect of wind shear[J]. Journal of Nanjing University of Aeronautics and Astronautics, 1996(3):98-103(in Chinese).
[24] 高正, 陈仁良. 直升机飞行动力学[M]. 北京:科学出版社, 2003. GAO Z, CHEN R L. Helicopter flight dynamics[M]. Beijing:Science Press, 2003(in Chinese).
CJA