需要介观流体的良好表示与较大长度和时间尺度的分子模拟相结合(De Fabritiis { \it et.等),Phys. Rev. Lett. 97,134501(2006))。然而,精确的计算模型的纳米级分子组件的流体动力学是缺乏的,至少部分是因为潜在的波动流体动力学方程的随机特性。本文在欧拉参考系中,在规则网格上对可压缩等温脉动流体动力学方程组进行有限体积离散。我们将其应用于流体,如氩在任意密度和水在环境条件下。为此,使用分子动力学模拟来导出所需的流体性质。该模型的平衡态被证明是一致的,并正确地再现线性流体力学,包括放松的声音和剪切模式。我们还考虑了非平衡态,包括在无滑移边界条件的空腔中的扩散和对流。
英文摘要:
A good representation of mesoscopic fluids is required to combine with molecular simulations at larger length and time scales (De Fabritiis {\it et. al}, Phys. Rev. Lett. 97, 134501 (2006)). However, accurate computational models of the hydrodynamics of nanoscale molecular assemblies are lacking, at least in part because of the stochastic character of the underlying fluctuating hydrodynamic equations. Here we derive a finite volume discretization of the compressible isothermal fluctuating hydrodynamic equations over a regular grid in the Eulerian reference system. We apply it to fluids such as argon at arbitrary densities and water under ambient conditions. To that end, molecular dynamics simulations are used to derive the required fluid properties. The equilibrium state of the model is shown to be thermodynamically consistent and correctly reproduces linear hydrodynamics including relaxation of sound and shear modes. We also consider non-equilibrium states involving diffusion and convection in cavities with no-slip boundary conditions.
Looking at bare transport coefficients in fluctuating hydrodynamics
Institute for Solid State Physics, University of Tokyo(东京大学固体物理研究所);Faculty of Engineering, Gifu University(岐阜大学工学部);Department of Physics, Kyoto University(京都大学物理学系)
Low Mach Number Fluctuating Hydrodynamics for Electrolytes
我们制定和计算研究低马赫数波动流体动力学方程的电解质溶液。我们有兴趣在中尺度的带电物种的混合物中研究运输,下到尺度低于德拜长度,热波动有显着的动态影响。继续我们以前关于不可压缩等温可混溶液体多组分混合物的波动流体力学的工作(A。Donev等人,Physics of Fluids,27,3,2015),我们现在使用准静电近似包括带电物质的影响。定域电荷产生一个电场,这反过来又在质量和动量方程中提供了额外的作用力。我们的低马赫数公式从完全可压缩公式中消除了声波,并导致计算效率更高的准不可压缩公式。我们证明了我们的能力,模拟盐水(NaCl)的解决方案在平衡和非平衡设置。我们表明,我们的算法是二阶的确定性设置,并为长度尺度远大于德拜长度得到的结果与电中性/双极近似。在随机环境中,我们的模型捕捉到了预测的动态平衡和非平衡波动。我们还确定和模型的不稳定性时,出现扩散混合发生在一个外加电场的存在下。
Thermodynamically Consistent Incorporation of the Langmuir Adsorption Model into Compressible Fluctuating Hydrodynamics
Korea Advanced Institute of Science and Technology(韩国科学技术院);San Jose State University(圣何塞州立大学);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室);University of California, Merced(加州大学默塞德分校)
Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室);Courant Institute of Mathematical Sciences, New York University(纽约大学柯朗数学科学研究所);Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine(纽约大学医学院心脏病学莱昂·H·查尼分部)
Low Mach Number Fluctuating Hydrodynamics of Binary Liquid Mixtures
Center for Computational Science and Engineering, Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室计算科学与工程中心);Courant Institute of Mathematical Sciences, New York University(纽约大学库朗数学科学研究所)
Low Mach Number Fluctuating Hydrodynamics of Diffusively Mixing Fluids
Courant Institute of Mathematical Sciences, New York University(纽约大学柯朗数学科学研究所);Center for Computational Science and Engineering, Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室计算科学与工程中心);Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine(纽约大学医学院医学部莱昂·H·查尼心脏病学分部);Department of Physics and Astronomy, San Jose State University(圣何塞州立大学物理与天文系)
Cross Correlators and Galilean Invariance in Fluctuating Ideal Gas Lattice Boltzmann Simulations
我们分析了Adhikari格子玻尔兹曼方法[Europhys. Lett. 71,473(2005)],并发现只要考虑稳定系统,即使对于小波长,它也显示出与理论的极好的一致性。这与其他有限差分和旧的格子玻尔兹曼实现相反,这些实现仅在大波长的限制下显示收敛。特别是交叉关联函数消失到小于0.5%。然而,对于较大的平均速度,伽利略不变性的违反表现出自己通过类似于那些早期的实现的幅度的错误。