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利用三维程序，对比研究了汇聚激波及平面激波冲击下SF6球形气泡演化规律的异同，以期发现激波的汇聚效应对界面演化的影响.三维程序采用多组分可压缩欧拉方程，基于有限体积法，利用MUSCL-Hancock格式进行数值求解，可以达到时间和空间的二阶精度.相比平面激波，汇聚激波由于存在曲率，且激波强度以及壁面效应在汇聚激波运行的过程中逐渐增强，使得激波冲击后的流场演化有较大的不同.计算结果表明：汇聚激波作用下，气泡界面的涡结构更加尖锐；气泡内部的透射激波聚焦程度更强，在界面下游附近形成的最高压力大于平面激波算例，由此产生的射流运动速度更快；由于汇聚激波曲率及激波强度的变化，导致界面上涡量的分布规律以及涡量幅值产生较大变化.通过界面上产生的环量以及界面内外气体混合速度的对比表明，汇聚激波更有助于涡量的产生以及气体的混合.因此激波的汇聚效应对气泡界面演化具有重要影响.The shock-bubble interaction is a basic configuration for studying the more general case of shock-accelerated inhomogeneous flows. In previous studies, a planar shock wave interacting with a spherical gas bubble was extensively investigated, in which the effects of shock intensity, Atwood number and secondary shock on the bubble development were considered and elucidated. However, in most of practical applications, such as inertial confinement fusion, a converging shock wave is generally involved. It is therefore of fundamental interest to explore the perturbation growth under converging shock conditions. Due to the difficulties encountered in generating a perfectly converging shock wave in laboratory, experimental investigation on the converging shock-accelerated inhomogeneous flows was seldom carried out previously. The preliminary study on the development of a gas bubble impacted by a converging shock wave showed that a large discrepancy exists compared with the planar counterparts. Because of the intrinsic three-dimensional (3D) features of this problem, the current experimental techniques are inadequate to explore the detailed differences between planar and converging shocks accelerating gas bubbles. As a result, numerical simulations become important and necessary. In this work, evolution of an SF6 spherical gas bubble surrounded by air accelerated by a cylindrical converging shock wave and a planar shock wave is numerically investigated by a 3D program, focusing on the convergence effect on the interface evolution. Multi-component compressible Euler equations are adopted in the 3D program and the finite volume method is used. The MUSCL-Hancock scheme, a second-order upwind scheme, is adopted to achieve the second-order accuracy on both temporal and spatial scales. Compared with planar shock wave, a cylindrical converging shock wave has curvature, and as the converging shock wave moves forward, the shock strength and the wall effect both increase, which will result in the diversity of the flow field after shock impact. The numerical results show that the vortex rings formed under converging shock condition are sharper than those under planar shock condition which may be associated with geometric contraction effect of the tube and reflected shock from the wall. Besides, the peak pressure generated in the vicinity of the downstream pole of the bubble under converging shock condition is higher than that of planar shock wave, and, therefore, the jet induced by high pressures moves faster under converging shock condition. Due to the variations of shock curvature and shock intensity, the distribution law and amplitude of vorticity generated by converging shock wave at the interface is changed. Comparison between circulation and gas mixing rate indicates that the converging shock is beneficial to promoting vorticity generation and gas mixing. From the present work, it can be concluded that the convergence effect plays an important role in interface evolution.
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Keywords:
- cylindrical converging shock wave /
- spherical gas bubble /
- three-dimensional /
- numerical simulation
[1] Ranjan D, Oakley J, Bonazza R 2011 Annu. Rev. Fluid Mech. 43 117
[2] Rudinger G, Somers L M 1960 J. Fluid Mech. 7 161
[3] Haas J F, Sturtevant B 1987 J. Fluid Mech. 181 41
[4] Layes G, Jourdan G, Houas L 2005 Phys. Fluids 17 028103
[5] Si T, Zhai Z G, Yang J M, Luo X S 2012 Phys. Fluids 24 054101
[6] Winkler K A, Chalmers J W, Hodson S W, Woodward P R, Zabusky N J 1987 Phys. Today 40 28
[7] Niederhaus J H, Greenough J A, Oakley J G, Ranjan D, Anderson M H, Bonazza R 2008 J. Fluid Mech. 594 85
[8] Zhu Y J, Dong G, Fan B C, Liu Y X 2012 Shock Waves 22 495
[9] Zhai Z G, Si T, Zou L Y, Luo X S 2013 Acta Mech. Sin. 29 24
[10] Sha S, Chen Z H, Zhang Q B 2015 Acta Phys. Sin. 64 015201 (in Chinese) [沙莎, 陈志华, 张庆兵 2015 64 015201]
[11] Sha S, Chen Z H, Xue D W 2013 Acta Phys. Sin. 62 144701 (in Chinese) [沙莎, 陈志华, 薛大文 2013 62 144701]
[12] Lindl J D, McCrory R L, Campbell E M 1992 Phys. Today 45 32
[13] Aglitskiy Y, Velikovich A L, Karasik M, Metzler N, Zalesak S T, Schmitt A J, Phillips L, Gardner J H, Serlin V, Weaver J L, Obenschain S P 2010 Philos. T. Roy. Soc. A 368 1739
[14] Bell G I 1951 Los Alamos National Laboratory, Los Alamos, NM, Report LA-1321
[15] Plesset M S 1954 J. Appl. Phys. 25 96
[16] Rayleigh L 1883 Proc. London Math. Soc. 14 170
[17] Taylor G 1950 Proc. R. Soc. London A 201 192
[18] Zhai Z G, Liu C L, Qin F H, Yang J M, Luo X S 2010 Phys. Fluids 22 041701
[19] Wang X S, Si T, Luo X S, Yang J M 2012 Acta Mech. Sin. 44 473 (in Chinese) [王显圣, 司廷, 罗喜胜, 杨基明 2012 力学学报 44 473]
[20] Si T, Zhai Z G, Luo X S, Yang J M 2014 Shock Waves 24 3
[21] Si T, Zhai Z G, Luo X S 2014 Laser Part. Beams 32 343
[22] Yang W H, Luo X S 2014 J. Univ. Sci. Technol. China 44 488 (in Chinese) [杨伟航, 罗喜胜 2014 中国科学技术大学学报 44 488]
[23] Zhai Z G, Si T, Luo X S, Yang J M 2011 Phys. Fluids 23 084104
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[1] Ranjan D, Oakley J, Bonazza R 2011 Annu. Rev. Fluid Mech. 43 117
[2] Rudinger G, Somers L M 1960 J. Fluid Mech. 7 161
[3] Haas J F, Sturtevant B 1987 J. Fluid Mech. 181 41
[4] Layes G, Jourdan G, Houas L 2005 Phys. Fluids 17 028103
[5] Si T, Zhai Z G, Yang J M, Luo X S 2012 Phys. Fluids 24 054101
[6] Winkler K A, Chalmers J W, Hodson S W, Woodward P R, Zabusky N J 1987 Phys. Today 40 28
[7] Niederhaus J H, Greenough J A, Oakley J G, Ranjan D, Anderson M H, Bonazza R 2008 J. Fluid Mech. 594 85
[8] Zhu Y J, Dong G, Fan B C, Liu Y X 2012 Shock Waves 22 495
[9] Zhai Z G, Si T, Zou L Y, Luo X S 2013 Acta Mech. Sin. 29 24
[10] Sha S, Chen Z H, Zhang Q B 2015 Acta Phys. Sin. 64 015201 (in Chinese) [沙莎, 陈志华, 张庆兵 2015 64 015201]
[11] Sha S, Chen Z H, Xue D W 2013 Acta Phys. Sin. 62 144701 (in Chinese) [沙莎, 陈志华, 薛大文 2013 62 144701]
[12] Lindl J D, McCrory R L, Campbell E M 1992 Phys. Today 45 32
[13] Aglitskiy Y, Velikovich A L, Karasik M, Metzler N, Zalesak S T, Schmitt A J, Phillips L, Gardner J H, Serlin V, Weaver J L, Obenschain S P 2010 Philos. T. Roy. Soc. A 368 1739
[14] Bell G I 1951 Los Alamos National Laboratory, Los Alamos, NM, Report LA-1321
[15] Plesset M S 1954 J. Appl. Phys. 25 96
[16] Rayleigh L 1883 Proc. London Math. Soc. 14 170
[17] Taylor G 1950 Proc. R. Soc. London A 201 192
[18] Zhai Z G, Liu C L, Qin F H, Yang J M, Luo X S 2010 Phys. Fluids 22 041701
[19] Wang X S, Si T, Luo X S, Yang J M 2012 Acta Mech. Sin. 44 473 (in Chinese) [王显圣, 司廷, 罗喜胜, 杨基明 2012 力学学报 44 473]
[20] Si T, Zhai Z G, Luo X S, Yang J M 2014 Shock Waves 24 3
[21] Si T, Zhai Z G, Luo X S 2014 Laser Part. Beams 32 343
[22] Yang W H, Luo X S 2014 J. Univ. Sci. Technol. China 44 488 (in Chinese) [杨伟航, 罗喜胜 2014 中国科学技术大学学报 44 488]
[23] Zhai Z G, Si T, Luo X S, Yang J M 2011 Phys. Fluids 23 084104
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