polymathic-ai/turbulent_radiative_layer_3D

在许多天体物理系统中，热气体相对于冷气体运动导致混合。混合产生了高度反应性的中间温度气体，在这种情况下会迅速冷却。在这个模拟中，底部是冷的密集气体，顶部是热的稀薄气体，它们以高度亚音速的速度相对运动。这种设置对开尔文-亥姆霍兹不稳定性是不稳定的，该不稳定性通过在不同模拟之间变化的小尺度噪声进行种子化。热气体和冷气体在热平衡状态下，加热和冷却完全平衡。然而，一旦由于开尔文-亥姆霍兹不稳定性引起的湍流导致混合发生，中间温度气体就会被填充。这些中间温度气体不在热平衡状态，冷却超过加热，导致从热相到冷相的净质量通量。这一过程发生在星际介质中，以及当冷云在周围的热介质中移动时的星系周围介质中。通过理解总冷却和质量传递如何随冷却速率变化，我们能够限制这一过程如何控制星系内部和周围气体的整体相结构、能量学和动力学。

In many astrophysical systems, hot gas moves relative to cold gas, which leads to mixing. Mixing populates intermediate temperature gas that is highly reactive — in this case it is rapidly cooling. In this simulation, there is cold, dense gas on the bottom and hot dilute gas on the top. They are moving relative to each other at highly subsonic velocities. This set up is unstable to the Kelvin Helmholtz instability, which is seeded with small scale noise that is varied between the simulations. The hot gas and cold gas are both in thermal equilibrium in the sense that the heating and cooling are exactly balanced. However, once mixing occurs as a result of the turbulence induced by the Kelvin Helmholtz instability, the intermediate temperatures become populated. This intermediate temperature gas is not in thermal equilibrium, and cooling beats heating. This leads to a net mass flux from the hot phase to the cold phase. This process occurs in the interstellar medium, and in the Circum-Galactic medium when cold clouds move through the ambient, hot medium. By understanding how the total cooling and mass transfer scale with the cooling rate, we are able to constrain how this process controls the overall phase structure, energetics and dynamics of the gas in and around galaxies.