论文标题
通过分子间电势在多原子气流中产生湍流
Creation of turbulence in polyatomic gas flow via an intermolecular potential
论文作者
论文摘要
我们为多原子气体开发了可拖动的相互作用模型，其动力学方程组合了由于分子间电位而引起的vlasov型平均场强迫，以及由于旋转相互作用而导致的玻尔兹曼型碰撞积分。我们为新的动力学方程构建了速度矩层次结构，并发现在较高的雷诺数条件下，压力方程与角动量和应力脱在一起。对于热通量，我们提出了一个新颖的封闭，可以开出气体流量的特定热容量。将特定的热容量设置为恒压过程的热量会导致平衡流的方程系统，在该方程中，动量传输方程包含平均场强迫，这是分子间电位的平均效应。值得注意的是，平衡流程方程不包含有关气体内部热力学特性的任何信息，因此适用于广泛的不同气体。我们在惯性流动方面的正常条件下进行类似气体的数值模拟，在整个域中压力是恒定的。我们发现，分子间电位的存在会产生明显的湍流，其时间平均的动能和温度的傅立叶光谱表现出Kolmogorov的功率衰减。
We develop a tractable interaction model for a polyatomic gas, whose kinetic equation combines a Vlasov-type mean field forcing due to an intermolecular potential, and a Boltzmann-type collision integral due to rotational interactions. We construct a velocity moment hierarchy for the new kinetic equation, and find that, under the high Reynolds number condition, the pressure equation becomes decoupled from the angular momentum and stress. For the heat flux, we propose a novel closure by prescribing the specific heat capacity of the gas flow. Setting the specific heat capacity to that of a constant-pressure process leads to the system of equations for a balanced flow, where the momentum transport equation contains the mean field forcing, which is an averaged effect of the intermolecular potential. Remarkably, the balanced flow equations do not contain any information about internal thermodynamic properties of the gas, and are thereby applicable to a broad range of different gases. We conduct numerical simulations for an air-like gas at normal conditions in the inertial flow regime, where the pressure is constant throughout the domain. We find that the presence of the intermolecular potential produces a distinctly turbulent flow, whose time-averaged Fourier spectra of the kinetic energy and temperature exhibit Kolmogorov's power decay.
