Abstract:In order to analyse the impact load and motion of an airplane during ditching, the ditching process of NACA TN2929 on the water was investigated by numerical simulations.The ditching strategy with various speed and pitch angle was concerned.The interactions between the airplane and water surface were simulated through solving the reynolds averaged navier-stokes(RANS) equations.The volume of Fluid(VOF) mothed was used to simulate the free surface.The overset grid method with dynamic fluid body interaction(DFBI) module was introduced to solve the coupled motion.The free fall water entry of a wedge and a cone was simulated.The convergence studies on the mesh size and time resolution for the analysis of airplane ditching were carried out and the results were further validated through comparing with the experimental data.Simulations of the airplane with different ditching velocities and various pitch angles were performed.The pressure distributions, the impact loads and the motion of the aeroplane were analysed.It is found the slamming load will reach a peak at 0.2 s after entering the water.The peak pressure at the bottom of the fuselage appears at the intersection of the free surface and the fuselage.The peak load is linearly related to the square of the landing speed.As the initial pitch angle increases, the peak slamming load will decrease slightly.
杨晓彬,许国冬. 基于重叠网格法的飞机水上降落水动力砰击载荷研究[J]. 振动与冲击, 2020, 39(2): 57-63.
YANG Xiaobin,XU Guodong. Identification of hydrodynamic impact loads during the airplane ditching-based on overset grid method. JOURNAL OF VIBRATION AND SHOCK, 2020, 39(2): 57-63.
[1] Thompson, W.C. Model ditching investigation of a jet transport airplane with various engine installations[R]. Technical Report Archive & Image Library, 1956.
[2] Steiner, M.F. Accelerations and bottom pressures measured on a B-24D airplane in a ditching test[R]. Technical Report Archive & Image Library, 1944.
[3] McBride, E.E. and Fisher, L.J. Experimental investigation of the effect of rear-fuselage shape on ditching behavior[R]. Technical Report Archive & Image Library, 1953.
[4] Von Karman, T. The impact on seaplane floats during landing[R]. Technical Report Archive & Image Library, 1929.
[5] Wagner, H. Über Stoß und Gleitvorgänge an der Oberfläche von Flüssigkeiten[J]. Z. Angew. Math. Mech; 1932,12:192-215.
[6] Korobkin, AA. Analytical models of water impact[J]. European Journal of Applied Mathematics, 2004, 15(6):821-838.
[7] Zhao, R and Faltinsen, OM. Aarsnes J. Water entry of arbitrary two-dimensional sections with and without separation[C]. Proc. 21st Symposium on Naval Hydrodynamics pp: 1996,118-133. Trondheim, Norway.
[8] Wu, G.X., Sun, H. and He, Y.S. Numerical simulation and experimental study of water entry of a wedge in free fall motion[J]. Journal of Fluids and Structures, 2004,19:277-289.
[9] Xu, G.D., Duan, W.Y. and Wu, G.X. Simulation of water entry of a wedge through free fall in three degrees of freedom[J]. Proceedings of the Royal Society A, 2010,466:2219-2239.
[10] Shigunov, V., Söding, H. and Zhou, Y. Numerical Simulation of Emergency Landing of Aircraft on a Plane Water Surface[C]. 2-Nd Int. Conf. on High-Perform. Marine Vehicles Hiper.2001.
[11] Bensch, L., Shigunov, V. and Söding, H. Computational method to simulate planned ditching of a transport airplane[J]. Computational Fluid & Solid Mechanics, 2003,1251-1254.
[12] Bisagni, C. and Pigazzini, M.S. Modelling strategies for numerical simulation of aircraft ditching[J]. International Journal of Crashworthiness, 2017,1-18.
[13] Guo, B.D., Liu, P.Q., Qu, Q.L. and Wang, J.W. Effect of pitch angle on initial stage of a transport airplane ditching[J]. Chinese Journal of Aeronautics, 2013,26(1), 17-26.
[14] 屈秋林, 胡茗轩, 郭昊,等. 整体运动网格法在飞机水上迫降模拟中的应用[J]. 航空科学技术, 2015(11):1-9.
Qiulin Q U, Mingxuan H U, Guo H, et al. Application of Global Moving Mesh in Aircraft Ditching Simulation[J]. Aeronautical Science & Technology, 2015(in Chinese).
[15] 罗琳胤, 杨仕福, 吕继航. 水陆两栖飞机着水响应模型与数值分析[J]. 机械设计, 2013, 30(8).
Luo L Y, Yang S F, Ji-Hang L V. Analysis and numeral simulation of water landing response model for amphibian[J]. Journal of Machine Design, 2013(in Chinese).
[16] 黄勇. 民用飞机水上迫降数值模拟计算研究[C]// 全国振动理论及应用学术会议. 2011.
Huang Y. Civil transport ditching simulation study[C]. National conference on vibration theory and application, 2011(in Chinese).
[17] Streckwall H, Lindenau O, Bensch L. Aircraft ditching: a free surface/free motion problem[J]. Archives of Civil & Mechanical Engineering, 2007, 7(3):177-190.
[18] Benek J.A., Steger J.L., Dougherty F.C. A flexible grid embedding technique with application to the Euler equations[J]. Aiaa Journal, 1983, 83.
[19] Benek J.A., Buning P.G., Steger J.L. A 3-D Chimera Grid Embedding TechniqueAIAA Paper 85-1523, 1985.
[20] Benek, J.A., Donegan, T.L., Suhs, N.E. Extended Chimera grid embedding scheme with application to viscous flows[C]. In the Proceedings of the 8th Computational Fluid Dynamics Conference. Honolulu, Hawaii, USA, AIAA-87-1126, 1987: 283–291.
[21] Hadzic H. Development and Application of Finite Volume Method for the Computation of Flows Around Moving Bodies on Unstructured, Overlapping Grids[J]. Technische Universität Harburg, 2006.
[22] 沈志荣. 船桨舵相互作用的重叠网格技术数值方法研究[D]. 上海交通大学, 2014.
[23] Shih, T.H., Liou, W.W., Shabbir, A., Yang, Z., and Zhu, J. A new k-epsilon eddy viscosity model for high reynolds number turbulent flows: model development and validation[J]. Computers & Fluids, 1995,24(3), 227-238.
[24] Hirt, C.W. and Nichols, B.D. Volume of fluid (vof) method for the dynamics of free boundaries[J]. Journal of Computational Physics, 1981,39(1), 201-225.
[25] Baldwin, J.L. Vertical water entry of cones[R], Naval Ordance Laboratory, White OAK, Silver Spring, Maryland.1971.