Abstract
The early evolution of an initially columnar vortex normal to a solid wall was examined. The vortex was generated by a pair of flaps in a water tank. Detrimental effects from the wall during the vortex generation were avoided by producing the vortex normal to a free surface and subsequently bringing a horizontal plate into contact with the surface. Digital particle image velocimetry (DPIV) measurements of the velocity and vorticity, together with laser induced fluorescence (LIF) visualizations, in a meridional plane revealed a toroidal structure with the appearance of an axisymmetric vortex breakdown bubble. Agreement was found between the measurements and numerical simulations of the axisymmetric Navier-Stokes equations. The results show that the flow in the effusive corner region is dominated by a Bödewadt-type spatially oscillatory boundary layer within the core region and a potential-like vortex boundary layer at large radii. The toroidal structure results from the interaction between these two boundary layers, leading to the roll up of a dominant shear layer within the Bödewadt structure, and does not develop from the columnar vortex itself.
Original language | English (US) |
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Pages (from-to) | 309-321 |
Number of pages | 13 |
Journal | Experiments in Fluids |
Volume | 29 |
Issue number | 4 |
DOIs | |
State | Published - Oct 2000 |
ASJC Scopus subject areas
- Computational Mechanics
- Mechanics of Materials
- Physics and Astronomy(all)
- Fluid Flow and Transfer Processes