Experimental Investigation on Cavity Characteristics during Water Entry of Disc-Headed Vehicle Assisted by Gas Jet Flow
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摘要: 针对跨介质航行体快速稳定穿越自由液面的需求, 以及目前跨介质过程中存在过大冲击载荷对结构和仪器的破坏、空泡溃灭与复杂非定常多相流动下的弹道失稳等问题，探索采用在航行体头部提供向前射流协助其快速稳定穿越自由液面, 射流穿透并改变自由液面的流场结构, 以达到降低过大载荷的目的。为研究气射流协助圆盘头部航行体入水空泡多相流动特性, 开展了向前喷气协助圆盘头部航行体入水实验。分析了入水过程中所形成的空泡形态, 以及气射流冲击液面过程中开口空泡的形成及演化过程, 探讨了不同通气口径和通气量对空泡直径、射流长度等的影响。实验结果表明: 开口空泡形成过程包括液面凹陷、液面振荡、形成流动和空泡形成4个阶段, 开口空泡直径和深度随通气口径增大而减小, 随通气量增大而增大。Abstract: The trans-medium vehicle is expected to quickly and stably break the free liquid surface. In addition, there are some problems in the trans-medium process, such as the damage to structures and instruments caused by the high impact load, cavity collapse, and ballistic trajectory instability caused by complex unsteady multiphase flow. To address these issues, a forward jet flow was provided at the head of the vehicle to make the vehicle quickly and stably break the free liquid surface. The jet flow penetrated and changed the flow field structure of the free liquid surface to reduce the high impact load. To investigate the multiphase flow characteristics of the cavity during water entry of the disc-headed vehicle assisted by gas jet, the water entry experiment of the disc-headed vehicle assisted by forward jet flow was carried out. The cavity morphology formed during water entry was analyzed, as well as the formation and evolution process of the broken cavity in the case of a gas jet flow impinging on the liquid surface. The effects of different ventilation nozzle diameters and ventilation flow rates on the cavity diameter and jet flow length were discussed. The experimental results indicate that the formation process of the broken cavity includes four stages, namely liquid surface depression, liquid surface oscillation, liquid flow, and cavity formation. The diameter and depth of the broken cavity decrease with the increase in ventilation nozzle diameter and increase with the increase in ventilation flow rate.
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Key words:
- trans-medium vehicle /
- water entry /
- gas jet /
- cavity
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图 4 空泡形态分类(开口空泡直径与通气系数对应关系)
Figure 4. Cavity pattern classification(The corresponding relationship between cavity diameter and ventilation coefficient)
图 5 向前喷气协助圆盘航行体垂直入水过程空泡形成及演化过程
Figure 5. The formation and evolution process of cavity during the forward jet assisted the disc vehicle vertical water-entry process
图 6 小通气系数下带气射流圆盘航行体冲击液面过程
Figure 6. The impact process of gas jet disc vehicle on water surface under small ventilation coefficient
图 7 空泡直径随时间的变化及其对应的空泡状态
Figure 7. The variation of the cavity diameter with time and its corresponding cavity state
图 9 空泡直径和射流长度随时间的变化(Dn=4 mm)
Figure 9. The variation of cavity diameter and jet length with time(Dn=4 mm)
图 10 空泡直径和射流长度随时间的变化(Dn=5 mm)
Figure 10. The variation of cavity diameter and jet length with time(Dn=5 mm)
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[1] Worthington A M. Impact with a liquid surface studied by the aid of instantaneous photography[J]. Philosophical Transactions of the Royal Society of London, 1900, 194(252-261): 175-199. [2] Von Kármán T. The impact on seaplane floats during landing[J]. National Advisory Committee for Aeronautics, 1929, 321: 309-313. [3] Chuang S. Experiments on flat-bottom slamming[J]. Journal of Ship Research, 1966, 10(1): 10-17. doi: 10.5957/jsr.1966.10.1.10 [4] Chuang S. Experiments on slamming of wedge-shaped bodies[J]. Journal of Ship Research, 1967, 11(3): 190-198. doi: 10.5957/jsr.1967.11.3.190 [5] Okada S, Sumi Y. On the water impact and elastic response of a flat plate at small impact angles[J]. Journal of Marine Science and Technology, 2000, 5(1): 31-39. doi: 10.1007/s007730070019 [6] Huera-Huarte F J, Jeon D, Gharib M. Experimental investigation of water slamming loads on panels[J]. Ocean Engineering, 2011, 38(11-12): 1347-1355. doi: 10.1016/j.oceaneng.2011.06.004 [7] Ermanyuk E V, Ohkusu M. Impact of a disk on shallow water[J]. Journal of Fluids and Structures, 2005, 20(3): 345-357. doi: 10.1016/j.jfluidstructs.2004.10.002 [8] Jiang Y, Shao S, Hong J. Experimental investigation of ventilated supercavitation with gas jet cavitator[J]. Physics of fluids, 2018, 30(1): 012103. doi: 10.1063/1.5005549 [9] Jiang Y, Zou Z, Yang L, et al. Reduction of water entry impact force by a gas jet[J]. Physical Review Fluids, 2023, 8(6): 64005. doi: 10.1103/PhysRevFluids.8.064005 [10] Li Y, Jiang Y, Shen L, et al. Experimental investigation on submerged water jet wrapped in an annular gas jet[J]. Physics of Fluids, 2023, 35(1): 012121. doi: 10.1063/5.0135351 [11] 杨茂, 王涵瑞, 邹志辉, 等. 通气协助航行体出水流动实验研究[J]. 兵器装备工程学报, 2022, 43(12): 29-33, 144. doi: 10.11809/bqzbgcxb2022.12.005Yang Mao, Wang Hanrui, Zou Zhihui, et al. Experimental investigation on ventilated cavity flow characteristics of the vehicle water exit[J]. Journal of Ordnance Equipment Engineering, 2022, 43(12): 29-33, 144. doi: 10.11809/bqzbgcxb2022.12.005 [12] 邹志辉, 李佳, 杨茂, 等. 喷气协助航行体入水空泡流动特性实验研究[J]. 弹道学报, 2022, 34(1): 1-8, 97. doi: 10.12115/j.issn.1004-499X(2022)01-001Zou Zhihui, Li Jia, Yang Mao, et al. Experimental investigation on cavity flow characteristics of water entry of vehicle with gas jet cavitator[J]. Journal of Ballistics, 2022, 34(1): 1-8, 97. doi: 10.12115/j.issn.1004-499X(2022)01-001 [13] Banks R B, Chandrasekhara D V. Experimental investigation of the penetration of a high-velocity gas jet through a liquid surface[J]. Journal of Fluid Mechanics, 1963, 15(1): 13-34. doi: 10.1017/S0022112063000021 [14] Rabbi R, Speirs N, Kiyama A, et al. Impact force reduction by consecutive water entry of spheres[J]. Journal of Fluid Mechanics, 2021, 915: A55. doi: 10.1017/jfm.2020.1165 [15] Hwang H Y, Irons G A. A water model study of impinging gas jets on liquid surfaces[J]. Metallurgical and Materials Transactions B, 2012, 43(2): 302-315. doi: 10.1007/s11663-011-9613-3 -
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