Cylindrical shock wave generated by a moving piston in a rotational axisymmetric non-ideal gas with conductive and radiative heat-fluxes in the presence of azimuthal magnetic field
Cylindrical shock wave generated by a moving piston in a rotational axisymmetric non-ideal gas with conductive and radiative heat-fluxes in the presence of azimuthal magnetic field
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DOI：
10.1016/j.actaastro.2018.10.041
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发表时间：
2019-03
影响因子：
3.5
通讯作者：
G. Nath
中科院分区：
文献类型：
--
作者：
G. Nath
研究了圆柱激波在具有热传导和辐射热流的旋转轴对称非理想气体中，由运动活塞驱动的方向磁场在空间上减小的情况下的传播。假定周围介质中的流体速度和方位磁场是变化的，并服从幂律。假定气体是导电的，并且服从简化的范德华状态方程。激波以变速运动，波的总能量是非恒定的。得到了激波后流场的相似解，并详细计算了阿尔芬马赫数、传热学和辐射传热参数、非理想性参数变化对激波后流场的影响。增大阿尔芬马赫数或增大气体的非理想参数，气体的可压缩性降低，因而冲击强度降低；而随着导热或辐射传热参数的增大，对压缩性能和冲击强度的影响则相反。结果表明，由于考虑了旋转介质，气体的可压缩性和抗冲击强度均有所提高。进一步研究了随着导热和辐射传热参数的增大，压力分布出现最大值和磁场分布出现最小值的趋势，涡量矢量的无量纲轴向分量减小。有趣的是，压力和密度在内表面（活塞）消失，因此在对称轴处形成真空，这与产生激波的实验室条件非常吻合。并对旋转介质和非旋转介质进行了比较。
The propagation of a cylindrical shock wave in a rotational axisymmetric non-ideal gas with heat conduction and radiation heat-flux, in the presence of a spatially decreasing azimuthal magnetic field, driven out by a moving piston is investigated. The fluid velocities and the azimuthal magnetic field in the ambient medium are assume to be varying and obeying power laws. The gas is assumed to be electrically conducting and obey a simplified van der Waals equation of state. The shock wave moves with variable velocity and the total energy of the wave is non-constant. Similarity solutions are obtained for the flow-field behind the shock and the effects of variation of Alfven Mach number, the conductive and radiative heat transfer parameters, the parameter of the non-idealness are worked out in detail. An increase in the value of Alfven Mach number or in the non-idealness parameter of the gas, decreases the compressibility of the gas and hence there is a decrease in the shock strength; whereas the reverse effects on compressibility and shock strength are obtained with an increase in conductive or radiative heat transfer parameter. It is shown that due to the consideration of rotating medium the compressibility of the gas and the shock strength increase. Further, it is investigated that with an increase in the parameters of conductive and radiative heat transfer the tendency of formation of maxima in the distribution of pressure and minimum in magnetic field and non-dimensional axial component of vorticity vector decreases. It is interesting to note that the pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the axis of symmetry, which is in excellent agreement with the laboratory conditions to produce a shock wave. A comparison between the cases of rotating and non-rotating medium is also made.