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arXiv 2411.09855physics.flu-dyncond-mat.mes-hall
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基于涨落流体动力学的球形与坐滴动力学研究

A Study of Spherical and Sessile Droplet Dynamics by Fluctuating Hydrodynamics

John B. Bell, Andrew Nonaka, Alejandro L. Garcia

AI总结:

本研究基于Cahn-Hilliard与不可压缩涨落流体动力学模型,模拟了纳米尺度下球形与坐滴的介观动力学,通过确定性迁移率测量与随机位置方差拟合对比计算扩散系数,发现特定滑移壁面及大接触角条件下两者结果存在差异。

摘要:

我们模拟了在热涨落显著的纳米尺度下由相分离流体形成的液滴的介观动力学。研究了完全浸没在第二种流体中的球形液滴,以及同时与固体表面接触的坐滴。我们的模型将Cahn-Hilliard表述与不可压缩涨落流体动力学相结合;对于坐滴,流体-固体接触角被指定为边界条件。通过施加体积力的确定性模拟来测量液滴的迁移率,并利用Einstein关系由此获得扩散系数。随机模拟则独立地通过对液滴位置方差随时间的线性拟合来获得扩散系数。在某些场景下,这两种测量给出相同的值,但对于在滑移壁面附近初始化的球形液滴,或者在滑移和无滑移表面上具有大接触角(大于90度)的坐滴情况则不然。

英文摘要:

We simulate the mesoscopic dynamics of droplets formed by phase separated fluids at nanometer scales where thermal fluctuations are significant. Both spherical droplets fully immersed in a second fluid and sessile droplets which are also in contact with a solid surface are studied. Our model combines a Cahn-Hillard formulation with incompressible fluctuating hydrodynamics; for sessile droplets the fluid-solid contact angle is specified as a boundary condition. Deterministic simulations with an applied body force are used to measure the droplets' mobility from which a diffusion coefficient is obtained using the Einstein relation. Stochastic simulations are independently used to obtain a diffusion coefficient from a linear fit of the variance of a droplet's position with time. In some scenarios these two measurements give the same value but not in the case of a spherical droplet initialized near a slip wall or in the case of sessile droplets with large contact angles (greater than 90 degrees) on both slip and no-slip surfaces.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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