Evolution of the initial hole in vertically vibrated shear thickening fluids.
Evolution of the initial hole in vertically vibrated shear thickening fluids.
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垂直振动剪切增稠流体中初始孔的演化。
DOI：
10.1103/physreve.83.056311
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Zhong Zhang
中科院分区：
文献类型：
--
作者：
Yulei Xu;Xinglong Gong;Yingqiang Sun;Shouhu Xuan;Wanquan Jiang;Zhong Zhang
剪切增稠流体（STF）的表观粘度随剪切速率的变化而变化，是其典型的流变特性。这种流变特性影响STF的垂直振动动力学特性。为了更好地了解STF的垂直振动动力学特性，研究了由聚甲基丙烯酸甲酯颗粒悬浮在乙二醇中制备的垂直振动STF的表面不稳定性。在临界驱动加速度以上，表面不稳定性由初始空穴的消失转变为初始空穴的分裂，初始空穴的分裂是通过对表面施加有限的扰动而产生的。初始孔洞消失所需的时间可以受到驱动加速度、振动频率、体积分数、厚度以及扰动的形状和大小的影响。提出了一种可能的模型，并利用静水压力和粘性耗散力的表达式阐明了空穴消失与剪切增稠效应之间的关系。裂变和扩散遵循六边形排列。在更高的加速度下，空穴以无序的状态覆盖整个表面。讨论了垂直振动剪切增稠流体中初始空穴的演化机理。
The apparent viscosity of shear thickening fluid (STF) changes dramatically with the applied shear rate, which is a typical rheological property of STF. Such a rheological property affects the vertically vibrated dynamic property of STF. In order to get a better understanding of the vertically vibrated dynamic properties of STF, the surface instabilities in vertically vibrated STF, which was prepared by suspending polymethylmethacrylate particles in ethylene glycol, are investigated. Above a critical driving acceleration, the surface instability transforms from the disappearance to the fission of the initial hole, which is produced by applying a finite perturbation to the surface. The time required for the initial hole to disappear can be affected by the driving acceleration, vibration frequency, volume fraction, thickness, and shape and size of the perturbation. A possible model is proposed, and the expressions of hydrostatic force and viscous dissipative force are employed to clarify the relationship between disappearance of the hole and shear thickening effect. The fission and spreading follow a hexagonal arrangement. At a higher acceleration, the holes cover the entire surface in a state of disorder. The mechanism for the initial hole's evolution in vertically vibrated shear thickening fluids is discussed.