Dynamical friction in an isentropic gas
Dynamical friction in an isentropic gas
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DOI：
10.1007/s10509-012-1041-6
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发表时间：
2012-03
影响因子：
1.9
通讯作者：
F. Khajenabi;S. Dib
中科院分区：
文献类型：
--
作者：
F. Khajenabi;S. Dib
当有引力的物体沿一定质量分布运动时，在其后面会产生一个过密的尾流。本文对等熵流和物体在其中作亚音速运动时远离物体的流场结构进行了分析研究，指出动摩擦力是物体上的主要阻力，并利用微扰理论得到了物体的密度。远离质量的扰动流的速度和压力。推导出等熵流中动态摩擦力的表达式，并表明其与流动马赫数和绝热指数的关系。我们发现动态摩擦力随着绝热指数的增大而减小。我们分析表明，尾流密度较低，在我们的等熵的情况下相比，等温的。
When a gravitating object moves across a given mass distribution, it creates an overdense wake behind it. Here, we performed an analytical study of the structure of the flow far from object when the flow is isentropic and the object moves subsonically within it. We show that the dynamical friction force is the main drag force on the object and by using a perturbation theory, we obtain the density, velocity and pressure of the perturbed flow far from the mass. We derive the expression of the dynamical friction force in an isentropic flow and show its dependence on the Mach number of the flow and on the adiabatic index. We find that the dynamical friction force becomes lower as the adiabatic index increases. We show analytically that the wakes are less dense in our isentropic case in comparison to the isothermal ones.