Chaudhri Anuj, Bell John B, Garcia Alejandro L, Donev Aleksandar
Computational Research Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA.
Department of Physics and Astronomy, San Jose State University, San Jose, California 95192, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Sep;90(3):033014. doi: 10.1103/PhysRevE.90.033014. Epub 2014 Sep 26.
Fluctuating hydrodynamics provides a model for fluids at mesoscopic scales where thermal fluctuations can have a significant impact on the behavior of the system. Here we investigate a model for fluctuating hydrodynamics of a single-component, multiphase flow in the neighborhood of the critical point. The system is modeled using a compressible flow formulation with a van der Waals equation of state, incorporating a Korteweg stress term to treat interfacial tension. We present a numerical algorithm for modeling this system based on an extension of algorithms developed for fluctuating hydrodynamics for ideal fluids. The scheme is validated by comparison of measured structure factors and capillary wave spectra with equilibrium theory. We also present several nonequilibrium examples to illustrate the capability of the algorithm to model multiphase fluid phenomena in a neighborhood of the critical point. These examples include a study of the impact of fluctuations on the spinodal decomposition following a rapid quench, as well as the piston effect in a cavity with supercooled walls. The conclusion in both cases is that thermal fluctuations affect the size and growth of the domains in off-critical quenches.
涨落流体动力学为介观尺度下的流体提供了一个模型，在该尺度下热涨落会对系统行为产生显著影响。在此，我们研究临界点附近单组分多相流的涨落流体动力学模型。该系统采用具有范德瓦尔斯状态方程的可压缩流公式进行建模，并纳入一个科特韦格应力项来处理界面张力。我们基于为理想流体的涨落流体动力学所开发算法的扩展，提出一种用于对此系统进行建模的数值算法。通过将测量的结构因子和毛细波谱与平衡理论进行比较，验证了该方案。我们还给出了几个非平衡示例，以说明该算法对临界点附近多相流体现象进行建模的能力。这些示例包括研究涨落对快速淬火后旋节线分解的影响以及具有过冷壁的腔体内的活塞效应。两种情况下的结论都是热涨落在非临界淬火中会影响畴的尺寸和生长。
