Normal velocity freeze-out of the Richtmyer-Meshkov instability when a rarefaction is reflected
Normal velocity freeze-out of the Richtmyer-Meshkov instability when a rarefaction is reflected
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当反映稀疏时，Richtmyer-Meshkov 不稳定性的正常速度冻结
DOI：
10.1103/physreve.91.023005
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发表时间：
2015
影响因子：
2.4
通讯作者：
J. Gustavo Wouchuk and Takayoshi Sano
中科院分区：
文献类型：
--
作者：
Zedgenizov;D.A.;Shatsky;V.S.;Panin;A.V.;Evtushenko;O.V.;Ragozin;A.L.;Kagi;H.;J. Gustavo Wouchuk and Takayoshi Sano
当激波阵面撞击分离两种不同流体的波纹接触面时，就会产生里希特迈尔-梅什科夫不稳定性（RMI）。入射激波折射后，总是形成一个透射激波，而另一个激波或稀疏波被反射回来。波纹波阵面产生的压力-熵-涡量场是两种流体产生流体动力学扰动的原因。在线性理论中，接触表面涟漪达到渐近法向速度，其取决于入射激波马赫数、流体密度比和压缩比。在过去，人们推测渐近法向速度为零的可能性，这种现象被称为“冻结”[G。Fraley，Phys. Fluids 29，376（1986）PFLDAS0031-917110.1063/1.865722; K. Mikaelian，Phys. Fluids 6，356（1994）PHFLE61070-663110.1063/1.868091，A. L. Velikovich，Phys. Plasmas 8，592（2001）PHPAEN 1070 -664X10.1063/1.1335829]。在以前的论文中，研究了冲击波在接触面反射时的冻结现象[J. G. Wouchuk和K. Nishihara，Phys.Rev.E70，026305（2004）PLEEE81539-375510.1103/PhysRevE.70.026305]。在这项工作中的RMI的冻结研究的情况下，其中的稀疏反射回来。两个不同的制度被发现：几乎相等的震前密度在界面处的任何冲击强度，和非常大的密度差的强冲击。在两种不同压缩比和相同压缩比的情况下，得到了激波马赫数与激波前密度比的等值线。不同情况下的冻结出的时间演变的分析。可以看出，冻结是不稳定界面和波纹波前之间的相互作用的结果。作为寻找冻结情况的一般和定性标准，可以看出，冻结的必要条件是在接触表面的每一侧处产生的切向速度的相同取向。与以前的作品的结果进行了比较。
The Richtmyer-Meshkov instability (RMI) develops when a shock front hits a rippled contact surface separating two different fluids. After the incident shock refraction, a transmitted shock is always formed and another shock or a rarefaction is reflected back. The pressure-entropy-vorticity fields generated by the rippled wave fronts are responsible for the generation of hydrodynamic perturbations in both fluids. In linear theory, the contact surface ripple reaches an asymptotic normal velocity which is dependent on the incident shock Mach number, fluids density ratio, and compressibilities. It was speculated in the past about the possibility of getting a zero value for the asymptotic normal velocity, a phenomenon that was called “freeze-out” [G. Fraley, Phys. Fluids 29, 376 (1986)PFLDAS0031-917110.1063/1.865722; K. Mikaelian, Phys. Fluids 6, 356 (1994)PHFLE61070-663110.1063/1.868091, A. L. Velikovich , Phys. Plasmas 8, 592 (2001)PHPAEN1070-664X10.1063/1.1335829]. In a previous paper, freeze-out was studied for the case when a shock is reflected at the contact surface [J. G. Wouchuk and K. Nishihara, Phys. Rev. E 70, 026305 (2004)PLEEE81539-375510.1103/PhysRevE.70.026305]. In this work the freeze-out of the RMI is studied for the case in which a rarefaction is reflected back. Two different regimes are found: nearly equal preshock densities at the interface at any shock intensity, and very large density difference for strong shocks. The contour curves that relate shock Mach number and preshock density ratio are obtained in both regimes for fluids with equal and different compressibilities. An analysis of the temporal evolution of different cases of freeze-out is shown. It is seen that the freeze-out is the result of the interaction between the unstable interface and the rippled wave fronts. As a general and qualitative criterion to look for freeze-out situations, it is seen that a necessary condition for freeze-out is the same orientation for the tangential velocities generated at each side of the contact surface at. A comparison with the results of previous works is also shown.