论文标题
两步过渡到对流流的分子提示通过流线渗透
Molecular hints of two-step transition to convective flow via streamline percolation
论文作者
论文摘要
对流是在许多不同领域重要的关键运输现象，从流体动力学和海洋循环到行星大气或恒星物理。但是，它的微观理解仍然具有挑战性。在这里，我们在重力场中的温度梯度下，在可压缩的（非贝贝克 - 贝索斯）硬盘流体中进行数值研究。我们发现了一个令人惊讶的两步过渡方案，并具有两个不同的临界温度。当底板温度达到第一个阈值时，对流会踢入（如结构化速度场所示），但与无重力病例相比，重力会导致阻碍热传输。在第二个（较高）的温度下，连接热和冷板的对流区的渗透过渡会触发有效的对流热传输。有趣的是，这张对流不稳定性的新颖图片为Navier-Stokes方程的未知分段解决方案打开了大门。
Convection is a key transport phenomenon important in many different areas, from hydrodynamics and ocean circulation to planetary atmospheres or stellar physics. However its microscopic understanding still remains challenging. Here we numerically investigate the onset of convective flow in a compressible (non-Oberbeck-Boussinesq) hard disk fluid under a temperature gradient in a gravitational field. We uncover a surprising two-step transition scenario with two different critical temperatures. When the bottom plate temperature reaches a first threshold, convection kicks in (as shown by a structured velocity field) but gravity results in hindered heat transport as compared to the gravity-free case. It is at a second (higher) temperature that a percolation transition of advection zones connecting the hot and cold plates triggers efficient convective heat transport. Interestingly, this novel picture for the convection instability opens the door to unknown piecewise-continuous solutions to the Navier-Stokes equations.
