The influence of the initial conditions on the water landing performance of an amphibious aircraft is investigated by solving the unsteady Reynolds-averaged Navier-Stokes equations coupled with the standard k-ω turbulence model. During simulation, the relationship among the aircraft, the mesh and the air-water interface is managed by the Arbitrary Lagrangian-Eulerian method with an improved computational mesh generation strategy. Based on this, the effects of the initial conditions including the incident angle, the descent velocity and the horizontal velocity on the landing performance are explored, meanwhile considering changes in parameters such as the overloads on the cockpit and the center of gravity, aerodynamics, hydrodynamics, the pitching angle and vertical displacement for the aircraft water landing process. Numerical results show that the amphibious aircraft experiences a relatively moderated load due to the increase of the initial incident angle. The cockpit experiences a much larger vertical overload value compared with that of others when the extreme value of pitching moments occurs. Furthermore, the overload of the aircraft reduces significantly as the descent velocity decreases. A linear relationship can be clearly established between the overloads on the center of gravity and the square of the downward velocities. Moreover, to obtain better landing performance on water, the aerodynamic lift caused by the horizontal flight velocity should be slightly larger than the aircraft gravity before landing.
[1] 黄领才, 雍明培. 水陆两栖飞机的关键技术和产业应用前景[J]. 航空学报, 2019, 40(1):522708. HUANG L C, YONG M P. Key technologies and industrial application prospects of amphibian aircraft[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(1):522708(in Chinese).
[2] YANG X B, WANG T M, LIANG J H, et al. Survey on the novel hybrid aquatic-aerial amphibious aircraft:Aquatic unmanned aerial vehicle (AquaUAV)[J]. Progress in Aerospace Sciences, 2015, 74:131-151.
[3] ROZHDESTVENSKY K V. Wing-in-ground effect vehicles[J]. Progress in Aerospace Sciences, 2006, 42(3):211-283.
[4] 申蒸洋, 陈孝明, 黄领才. 大型水陆两栖飞机特殊任务模式对总体设计的挑战[J]. 航空学报, 2019, 40(1):522400. SHEN Z Y, CHEN X M, HUANG L C. Challenges for aircraft design due to special mission models of large-scale amphibious aircraft[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(1):522400(in Chinese).
[5] WANG L X, YIN H P, YANG K, et al. Water takeoff performance calculation method for amphibious aircraft based on digital virtual flight[J]. Chinese Journal of Aeronautics, 2020, 33(12):3082-3091.
[6] 黄淼, 褚林塘, 李成华, 等. 大型水陆两栖飞机抗浪能力研究[J]. 航空学报, 2019, 40(1):522335. HUANG M, CHU L T, LI C H, et al. Seakeeping performance research of large amphibious aircraft[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(1):522335(in Chinese).
[7] 唐彬彬, 吴彬, 王明振, 等. 抑波槽宽度对水陆两栖飞机喷溅性能影响对比试验研究[J]. 航空科学技术, 2015, 26(1):73-78. TANG B B, WU B, WANG M Z, et al. Comparative test study for the effect of groove type spray suppressor widths on amphibious aircraft spray performance[J]. Aeronautical Science & Technology, 2015, 26(1):73-78(in Chinese).
[8] NASA. PB2Y-3 aircraft model test[EB/OL]. (2011-05-19)[2020-05-26]. https://www.youtube.com/watch?v=vA-OLK94Vi4.
[9] NASA. Gru mman JRF-5 water landings[EB/OL]. (2011-07-15)[2020-05-26]. https://www.youtube.com/watch?v=y9ESt4Ut0eU.
[10] 唐彬彬, 张家旭, 李成华, 等. 水陆两栖飞机模型喷溅峰点分析方法研究[J]. 航空计算技术, 2015, 45(6):45-46, 51. TANG B B, ZHANG J X, LI C H, et al. Study on analytical method for spray peaks of amphibious aircraft[J]. Aeronautical Computing Technique, 2015, 45(6):45-46, 51(in Chinese).
[11] 段旭鹏, 孙卫平, 魏猛, 等. 基于OpenFOAM的水陆两栖飞机水面高速滑行研究[J]. 航空学报, 2019, 40(1):522330. DUAN X P, SUN W P, WEI M, et al. Numerical simulation of amphibious aircraft taxiing at high speed on water using OpenFOAM[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(1):522330(in Chinese).
[12] DUAN X P, SUN W P, CHEN C, et al. Numerical investigation of the porpoising motion of a seaplane planing on water with high speeds[J]. Aerospace Science and Technology, 2019, 84:980-994.
[13] 马增辉, 刘立胜, 岳珍, 等. 水陆两栖飞机波浪水面上降落耐波性数值分析[J]. 计算力学学报, 2018, 35(3):380-386. MA Z H, LIU L S, YUE Z, et al. Numerical investigation on seakeeping performance of amphibious aircraft landing on waves[J]. Chinese Journal of Computational Mechanics, 2018, 35(3):380-386(in Chinese).
[14] 孙丰, 吴彬, 廉滋鼎, 等. 着水姿态对大型水陆两栖飞机着水性能的影响[J]. 船舶力学, 2019, 23(4):397-404. SUN F, WU B, LIAN Z D, et al. Influence of pitch angle on water-entry performance of large-scale amphibian aircraft hull[J]. Journal of Ship Mechanics, 2019, 23(4):397-404(in Chinese).
[15] QIU L J, SONG W B. Efficient decoupled hydrodynamic and aerodynamic analysis of amphibious aircraft water takeoff process[J]. Journal of Aircraft, 2013, 50(5):1369-1379.
[16] QIU L J, SONG W B. Efficient multiobjective optimization of amphibious aircraft fuselage steps with decoupled hydrodynamic and aerodynamic analysis models[J]. Journal of Aerospace Engineering, 2016, 29(3):04015071.
[17] SIEMANN M H, LANGRAND B. Coupled fluid-structure computational methods for aircraft ditching simulations:Comparison of ALE-FE and SPH-FE approaches[J]. Computers & Structures, 2017, 188:95-108.
[18] HIRT C W, NICHOLS B D. Volume of fluid (VOF) method for the dynamics of free boundaries[J]. Journal of Computational Physics, 1981, 39(1):201-225.
[19] 孙华伟. 滑行面形状对滑行艇阻力与航态影响数值分析[D]. 哈尔滨:哈尔滨工程大学, 2012:42-43. SUN H W. Numerical analysis of planing-hull surface shape on resistance and sailing attitude[D]. Harbin:Harbin Engineering University, 2012:42-43(in Chinese).
[20] 卢昱锦, 肖天航, 李正洲. 高速平板着水数值模拟[J]. 航空学报, 2017, 38(增刊1):721498. LU Y J, XIAO T H, LI Z Z. Numerical simulation of high speed plate ditching[J]. Acta Aeronautica et Astronautica Sinica, 2017, 38(Sup1):721498(in Chinese).
[21] 金禹彤, 陈吉昌, 卢昱锦, 等. 楔形体入波浪水面数值模拟[J]. 航空学报, 2019, 40(10):122854. JIN Y T, CHEN J C, LU Y J, et al. Numerical simulation of wedge impacting on wavy water[J]. Acta Aeronautica et Astronautica Sinica, 2019, 40(10):122854(in Chinese).
[22] XU L, TROESCH A W, PETERSON R. Asymmetric hydrodynamic impact and dynamic response of vessels[J]. Journal of Offshore Mechanics and Arctic Engineering, 1999, 121(2):83-89.
[23] PANCIROLI R, ABRATE S, MINAK G. Dynamic response of flexible wedges entering the water[J]. Composite Structures, 2013, 99:163-171.
[24] MEI X M, LIU Y M, YUE D K P. On the water impact of general two-dimensional sections[J]. Applied Ocean Research, 1999, 21(1):1-15.
[25] 褚林塘. 水上飞机水动力设计[M]. 北京:航空工业出版社, 2014:84-93. CHU L T. Seaplane hydrodynamic design[M]. Beijing:Aviation Industry Press, 2014:84-93(in Chinese).
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