弹体水平入水的空泡扩展相关特性研究
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摘要
利用轻气炮设备对平头、半球型、截卵形柱形弹以及圆球形弹进行了速度在100～300 m/s的水平入水试验。利用高速相机记录了弹体入水和空泡扩展的详细过程,用能量守恒的观点间接考察了空泡内外压差Δp随入水侵彻位移的变化规律,同时研究了入水弹道上不同截面处的空泡扩展速度特性及空泡半径达到最大时的平均扩展速度。结果表明空泡内外压差Δp沿侵彻深度总体上有两种变化模式,同一工况下,侵彻轨迹上不同截面处的空泡壁扩展平均速度基本一致;试验结果与理论计算吻合较好。
In this paper, the horizontal water-entry experiments of flat, hemispherical, truncated-ogival and spherical projectiles at the velocity range of 100—300 m/s have been conducted with a light-gas gun. The whole water entry and cavitation expansion processes were recorded by a high-speed camera. Variation laws of the pressure difference Δp along the penetration distance were indirectly investigated by the principle of energy conservation. Moreover, the average cavity wall velocity at different cavity sections which are along the penetration distance was also studied. Two variation laws were found for the pressure difference Δp, and results show that the average cavity wall velocity remains consistent basically for different cavity sections along the ballistic trajectory which is in the same water-entry condition. Good agreements were observed between experimental and analytical results.
In this paper, the horizontal water-entry experiments of flat, hemispherical, truncated-ogival and spherical projectiles at the velocity range of 100—300 m/s have been conducted with a light-gas gun. The whole water entry and cavitation expansion processes were recorded by a high-speed camera. Variation laws of the pressure difference Δp along the penetration distance were indirectly investigated by the principle of energy conservation. Moreover, the average cavity wall velocity at different cavity sections which are along the penetration distance was also studied. Two variation laws were found for the pressure difference Δp, and results show that the average cavity wall velocity remains consistent basically for different cavity sections along the ballistic trajectory which is in the same water-entry condition. Good agreements were observed between experimental and analytical results.
引文
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[15]张志宏,孟庆昌,顾建农,等.水下超声速细长锥型射弹超空泡形态的计算方法[J].爆炸与冲击,2011(1):49-54.ZHANG Zhihong,MENG Qingchang,GU Jiannong,et al.Acalculation method for supercavity profile about a slender cone-shaped projectile traveling in water at supersonic speed[J].Explosion and Shock Waves,2011(1):49-54.
[16]张志宏,孟庆昌,金永刚,等.超声速细长锥型射弹超空泡流动数值计算方法[J].华中科技大学学报(自然科学版),2014(1):39-43.ZHANG Zhihong,MENG Qingchang,JIN Yonggang,et al.Numerical method of supercavitating flow past a slender cone type projectile traveling at supersonic speed[J].Journal of Huazhong University of Science and Technology(Natural Science),2014(1):39-43.
[17]孟庆昌,张志宏,李启杰.高速射弹超空泡流动的重力和压缩性效应[J].爆炸与冲击,2016(6):781-788.MENG Qingchang,ZHANG Zhihong,LI Qijie.Effects of gravity and compressibility on supercavitating flow caused by high speed projectile[J].Explosion and Shock Waves,2016(6):781-788.
[2]MAY A.Vertical entry of missiles into water[J].Journal of Applied Physics,1952,23:1362-1372.
[3]BIRKHOFF G,ISAACS R.Transient cavities in air-water entry[R].[S.l.]:NAVORD Report,1951.
[4]LEE M,LONGORIA R,WILSON D.Cavity dynamics in high-speed water entry[J].Physics of Fluids,1997,9:540-550.
[5]DUCLAUX,CAILLF,DUEZ C,et al.Dynamics of transient cavities[J].Journal of Fluid Mechanics,2007,591:1-19.
[6]ARISTOFF J,BUSH J.Water entry of small hydrophobic spheres[J].Journal of Fluid Mechanics,2009,619:45-78.
[7]GUO Z T,ZHANG W,XIAO X K,et al.An investigation into horizontal water entry behaviors of projectiles with different nose shapes[J].International Journal of Impact Engineering,2012,49:43-60.
[8]GUO Zitao,ZHANG Wei,WANG Cong.Experimental and theoretical study on the high-speed horizontal water entry behaviors of cylindrical projectiles[J].Journal of Hydrodynamics,2012,24(2):217-225.
[9]YAO E R,WANG H R,PAN L,et al.Vertical water-entry of bullet-shaped projectiles[J].Journal of Applied Mathematics and Physics,2014,2:323-334.
[10]BODILY K G,CARLSON S J,TRUSCOTT T T.The water entry of slender axisymmetric bodies[J].Physics of Fluids,2014,26:1-37.
[11]HE Chuntao,WANG Cong,WEI Yingjie,et al.Numerical simulation of pressure distribution in vertical water-entry cavity[J].Journal of Ship Mechanics,2011(9):960-968.
[12]孙钊,曹伟,王聪.球体垂直入水过程流体动力数值研究[J].振动与冲击,2017,36(20):165-172.SUN Zhao,CAO Wei,WANG Cong.Numerical investigations of hydrodynamic force acting on sphere during water entry[J].Journal of Vibration and Shock,2017,36(20):165-172.
[13]路中磊,魏英杰,王聪,等.正浮力开放腔体圆柱壳垂直入水数值研究[J].振动与冲击,2016,35(16):79-85.LU Zhonglei,WEI Yingjie,WANG Cong,et al.Numerical study on vertical water-entry of cylindrical structure with positive buoyancy and un-closed solid cavity[J].Journal of Vibration and Shock,2016,35(16):79-85.
[14]张志宏,孟庆昌,顾建农,等.水下亚声速细长锥型射弹超空泡形态的计算方法[J].爆炸与冲击,2010(3):254-261.ZHANG Zhibong,MENG Qingchang,GU Jiannong,et al.Acalculation method cone-shaped projectile for supercavity profile about a traveling in water at subsonic speed[J].Explosion and Shock Waves,2010(3):254-261.
[15]张志宏,孟庆昌,顾建农,等.水下超声速细长锥型射弹超空泡形态的计算方法[J].爆炸与冲击,2011(1):49-54.ZHANG Zhihong,MENG Qingchang,GU Jiannong,et al.Acalculation method for supercavity profile about a slender cone-shaped projectile traveling in water at supersonic speed[J].Explosion and Shock Waves,2011(1):49-54.
[16]张志宏,孟庆昌,金永刚,等.超声速细长锥型射弹超空泡流动数值计算方法[J].华中科技大学学报(自然科学版),2014(1):39-43.ZHANG Zhihong,MENG Qingchang,JIN Yonggang,et al.Numerical method of supercavitating flow past a slender cone type projectile traveling at supersonic speed[J].Journal of Huazhong University of Science and Technology(Natural Science),2014(1):39-43.
[17]孟庆昌,张志宏,李启杰.高速射弹超空泡流动的重力和压缩性效应[J].爆炸与冲击,2016(6):781-788.MENG Qingchang,ZHANG Zhihong,LI Qijie.Effects of gravity and compressibility on supercavitating flow caused by high speed projectile[J].Explosion and Shock Waves,2016(6):781-788.