MOTIONS OF ANISOTROPIC PARTICLES - APPLICATION TO VISUALIZATION OF 3-DIMENSIONAL FLOWS

The aim of the paper is to get insight into flow patterns visualized b y suspended anisotropic reflective particles. The motion of triaxial e llipsoids embedded in a three-dimensional flow, i.e., which cannot be reduced to a local plane Couette flow, is calculated. Both the asympto tic trajectory and the transient time to reach it are discussed. These results are used to simulate laser sheet visualizations of two classi cal three-dimensional flows (Taylor-Couette vortices and flow between rotating disks) where the particle history is shown to be negligible. The simulated visualizations are well compared to experimental ones bu t the paper addresses the fact that the legitimate question of what sh ows the visualization does not have a simple answer. Nevertheless, the se results open the way for quantitative comparisons between computati onal fluid dynamics and experimental visualizations. (C) 1998 American Institute of Physics.