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arXiv 1302.6311nucl-thhep-phhep-thphysics.flu-dyn
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基于弛豫时间近似的相对论耗散流体力学

Relativistic dissipative hydrodynamics from kinetic theory with relaxation time approximation

Amaresh Jaiswal

摘要:

本文从碰撞项采用弛豫时间近似的Boltzmann方程出发,对接近平衡态的分布函数采用Chapman-Enskog展开式,直接从耗散量的定义出发,导出了耗散量的流体动力学演化方程。虽然方程的形式与传统的Israel-Stewart方法采用Grad的14阶矩近似和Boltzmann方程的二阶矩得到的方程相同,但得到的系数不同。在一维标度展开的情况下,我们证明了我们的结果与Boltzmann方程的数值解相比,Israel-Stewart的结果更好地符合。我们还表明,包括近似高阶修正粘性演化显着提高了这种协议,从而证明了弛豫时间近似的碰撞项。

英文摘要:

Starting from Boltzmann equation with relaxation time approximation for the collision term and using Chapman-Enskog like expansion for distribution function close to equilibrium, we derive hydrodynamic evolution equations for the dissipative quantities directly from their definition. Although the form of the equations is identical to those obtained in traditional Israel-Stewart approaches employing Grad's 14-moment approximation and second moment of Boltzmann equation, the coefficients obtained are different. In the case of one-dimensional scaling expansion, we demonstrate that our results are in better agreement with numerical solution of Boltzmann equation as compared to Israel-Stewart results. We also show that including approximate higher-order corrections in viscous evolution significantly improves this agreement, thus justifying the relaxation time approximation for the collision term.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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