Title: Derivation of fluid dynamics from kinetic theory with the 14--moment approximation Show Chinese title

Title: 从 kinetic 理论推导流体力学的 14-矩近似

Abstract: We review the traditional derivation of the fluid-dynamical equations from kinetic theory according to Israel and Stewart. We show that their procedure to close the fluid-dynamical equations of motion is not unique. Their approach contains two approximations, the first being the so-called 14-moment approximation to truncate the single-particle distribution function. The second consists in the choice of equations of motion for the dissipative currents. Israel and Stewart used the second moment of the Boltzmann equation, but this is not the only possible choice. In fact, there are infinitely many moments of the Boltzmann equation which can serve as equations of motion for the dissipative currents. All resulting equations of motion have the same form, but the transport coefficients are different in each case. Show Chinese abstract

Abstract: 我们回顾了根据以色列和斯图尔特的理论从 kinetic theory 推导流体动力学方程的传统方法。 我们表明，他们用于闭合流体动力学运动方程的方法不是唯一的。 他们的方法包含两个近似，第一个是所谓的 14-moment 近似来截断单粒子分布函数。 第二个涉及耗散电流的运动方程的选择。 以色列和斯图尔特使用了玻尔兹曼方程的二阶矩，但这不是唯一可能的选择。 事实上，玻尔兹曼方程有无穷多个矩可以作为耗散电流的运动方程。 所有得到的运动方程形式相同，但在每种情况下输运系数不同。