Sphere wake dynamics

Authors: Prahl Wittberg, L., Revstedt, J., Fuchs, L.F.
Document Type: Conference
Pubstate: Published
Journal: 2nd Int. Conf. on Jets, Wakes and Separated Flows, Sept 16-19, 2008, Berlin, Germany
Year: 2008


Understanding the flow behavior around spheres are of great importance when it comes to improve the efficiency of any industrial application involving multiphase flow systems. The purpose with this study is to continue the work and further investigate the wake dynamics behind interacting spheres under steady and periodic free-stream conditions. Both single and dual sphere formations are considered, focusing on Reynolds number at values around which, flow transitions have been found to occur. The results shows that "lock--on" to the free-stream frequency is more likely to occur for free-stream frequencies greater than the frequency associated with the natural vortex shedding. The appearance of a low frequency can often be related to a swirling motion of the wake. Also, the vortex shedding for tandem formations are delayed at short inter-particle distances and the vortical structures in the flow field of two spheres in tandem are different as compared to those observed for a single sphere.