Visualization of Vortex Breakdown Structures

Subtitle: Dedicated to Professor Dr.-Ing., Dr.techn. E.h. Jürgen Zierep on the occasion of his 70th birthday.

Article type: Research Article

Authors: Bühler, K.

Affiliations: University of Applied Science (Fachhochschule), Badstrasse 24, D-77652 Offenburg, Germany

Abstract: Shapes and structures of vortex breakdown phenomena in rotating fluids are visualized. We investigate the flow in a cylindrical container and in a cone between two spherical surfaces. The primary swirling flow is induced by the rotating upper disk in the cylindrical case and by the lower boundary in the spherical case. The upper surface can be fixed with a no slip condition or can be a stress-free surface. Depending on these boundary conditions and on the Reynolds number novel structures of recirculation zones are realized. Experiments are done to visualize the topological structure of the flow and to determine their existence range as function of the geometry and rotation rate. A comparison between the experimental and theoretical approach shows a good agreement in respect to the topological structures of the flows.

Keywords: vortex breakdown, rotating fluids, recirculation zones, confined geometries, fixed and stress-free boundaries, flow visualization

Journal: Journal of Visualization, vol. 2, no. 1, pp. 25-30, 1999