Method to calculate electrical forces acting on a sphere in an electrorheological fluid.
Method to calculate electrical forces acting on a sphere in an electrorheological fluid.
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DOI：
10.1103/physreve.71.031503
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发表时间：
2005-01
期刊：
影响因子：
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通讯作者：
Kwangmoo Kim;D. Stroud;Xiangting Li;D. Bergman
中科院分区：
文献类型：
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作者：
Kwangmoo Kim;D. Stroud;Xiangting Li;D. Bergman
我们描述了一种计算作用在具有不同介电常数的主体中的介电球悬浮体中的球体上的电力的方法，假设施加空间均匀电场。该方法使用复合材料总静电能的光谱表示。力表示为该能量的某个梯度，可以用封闭的解析形式来表示，而不是作为数值导数来评估。即使球体和主体都具有频率相关的介电函数和非零电导率，只要系统处于准静态状态，该方法也适用。原则上，它包括所有多极对力的贡献，并且可用于计算多体以及成对力。我们还提供了几个数值示例，包括具有有限电导率的主流体。正如预期的那样，在大间距下，球体之间的力接近偶极-偶极极限，但当球体几乎接触时，则大大偏离该极限。当主体是微导电流体时，力也可能随着频率的函数而改变符号。
We describe a method to calculate the electrical force acting on a sphere in a suspension of dielectric spheres in a host with a different dielectric constant, under the assumption that a spatially uniform electric field is applied. The method uses a spectral representation for the total electrostatic energy of the composite. The force is expressed as a certain gradient of this energy, which can be expressed in a closed analytic form rather than evaluated as a numerical derivative. The method is applicable even when both the spheres and the host have frequency-dependent dielectric functions and nonzero conductivities, provided the system is in the quasistatic regime. In principle, it includes all multipolar contributions to the force, and it can be used to calculate multibody as well as pairwise forces. We also present several numerical examples, including host fluids with finite conductivities. The force between spheres approaches the dipole-dipole limit, as expected, at large separations, but departs drastically from that limit when the spheres are nearly in contact. The force may also change sign as a function of frequency when the host is a slightly conducting fluid.