Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA.
Phys Rev Lett. 2011 May 20;106(20):204501. doi: 10.1103/PhysRevLett.106.204501. Epub 2011 May 16.
We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. We find good agreement between a simple fluctuating hydrodynamics theory and particle and finite-volume simulations. The enhancement of the diffusive transport depends on the system size L and grows as ln(L/L₀) in quasi-two-dimensional systems, while in three dimensions it scales as L₀⁻¹ - L⁻¹, where L₀ is a reference length. Our results demonstrate that fluctuations play an important role in the hydrodynamics of small-scale systems.
我们研究了热速度涨落的平流对两种相同流体混合物中的有效扩散系数的贡献。我们发现简单的涨落流体力学理论与粒子和有限体积模拟之间存在良好的一致性。扩散输运的增强取决于系统尺寸 L，并在准二维系统中以 ln(L/L₀)的形式增长，而在三维中则以 L₀⁻¹ - L⁻¹的形式缩放，其中 L₀是参考长度。我们的结果表明，涨落在小尺度系统的流体动力学中起着重要作用。
