Experimental Studies of Two-dimensional Laminar Jet Flows in Freely Suspended Liquid Crystal Films
Kyle R. Ferguson, Evan Dutch, Zhiyuan Qi, Adam Green, Carlos Alas, Corrina Briggs, Cheol Soo Park, Matthew A. Glaser, Joseph E. Maclennan, Noel A. Clark
Two dimensional (2D) laminar jet-----a stream of fluid that projected into a surrounding medium with the flow confined in 2D-----has both theoretical and experimental significance. We carried out 2D laminar jet experiments in freely suspended liquid crystal films (FSLCFs) of nanometers thick and centimeters in size, in which individual molecules are confined to single layers thus enable film flows with two degrees of freedom. The experimental observations are found in good agreement with the classic 2D laminar jet theory of ideal cases that assume no external coupling effects, even in fact there exist strong coupling force from the ambient air. We further investigated this air coupling effect in computer simulations, with the results indicated air has little influence on the velocity maps of flow near the nozzle. This astonishing results could be intuitively understood by considering 2D incompressibility of the films. This experiment, together with a series of our previous experiments, show for a wide range of Reynolds number, FSLCFs are excellent testing beds for 2D hydrodynamics.
Finite difference method in prolate spheroidal coordinates for freely suspended spheroidal particles in linear flows of viscous and viscoelastic fluids
Hydrodynamic interactions of spherical particles in Poiseuille flow between two parallel walls
本文研究了无限平壁通道中入射Poillille流中球形颗粒的流体动力学相互作用。颗粒悬浮在牛顿流体中，并假设蠕动流动条件。使用我们的高精度笛卡尔表示算法[Physica A xxx，{ \bf xx}，2005]获得的数值结果，提出了一个单一的领域，两个领域，和许多领域的阵列。我们考虑自由悬浮颗粒的运动以及作用在吸附在壁面上的颗粒上的力和力矩。我们发现，对流体动力学相互作用在这个壁有界的系统有一个复杂的依赖于横向粒子间的距离，由于在颗粒表面之间的间隙和回流与存在的墙壁的耗散的综合效应。对于不动的粒子对，我们已经研究了几个远场渐近制度之间的交叉对应于不同的关系之间的颗粒分离和距离的颗粒从墙壁。我们还表明，远场流的累积效应，大大影响力的分布在阵列中的不动的球体。因此，远场的贡献必须包括在任何可靠的算法来评估多粒子的流体动力学相互作用的平行壁几何形状。
