标题： 非牛顿流体和牛顿流体在压力作用下在固体基底上的扩展 显示英文标题

标题： Spreading of Non-Newtonian and Newtonian Fluids on a Solid Substrate under Pressure

摘要： 强非牛顿流体，即淀粉水凝胶，被证明在受载时表现出粘弹性行为。我们研究了木薯和马铃薯淀粉凝胶。当流体一滴被夹在两片玻璃板之间并被压缩时，流体与板之间的接触面积以振荡的方式增加。这与牛顿流体在类似情况下面积单调增加的情况不同。此外，边缘还出现一种不稳定性，看起来类似于萨弗曼-泰勒指状物。这在压缩下通常不会出现。加载历史也被发现会影响扩散的方式。我们尝试通过一种结合广义微积分的粘弹性模型来描述流体的非牛顿特性。这被证明可以定性地再现表面应变的振荡变化。 显示英文摘要

摘要： Strongly non-Newtonian fluids namely, aqueous gels of starch, are shown to exhibit visco-elastic behavior, when subjected to a load. We study arrowroot and potato starch gels. When a droplet of the fluid is sandwiched between two glass plates and compressed, the area of contact between the fluid and plates increases in an oscillatory manner. This is unlike Newtonian fluids, where the area increases monotonically in a similar situation. The periphery moreover, develops an instability, which looks similar to Saffman Taylor fingers. This is not normally seen under compression. The loading history is also found to affect the manner of spreading. We attempt to describe the non-Newtonian nature of the fluid through a visco-elastic model incorporating generalized calculus. This is shown to reproduce qualitatively the oscillatory variation in the surface strain.