arXiv subjects

Gustavo Sarasua

Publications and source records attributed to Gustavo Sarasua.

2 recordsLinked to original sources

arXiv2008

Influence of coaxial cylinders on vortex breakdown in a closed flow

The effect of fixed cylindrical rods located at the centerline axis on vortex breakdown (VB) is studied experimentally and numerically. We find that the VB is enhanced for very small values of the rod radius $d$, while it is suppressed for values of $d$ beyond a critical value. In order to characterize this effect, the critical Reynolds number for the appearance of vortex breakdown as a function of the radius of the fixed rods and the different aspect ratios was accurately determined, using digital particle image velocimetry. The numerical and experimental results are compared showing an excellent agreement. In addition, a simple model in order to show that this effect also appears in open pipe flows is presented in the appendix.

physics.flu-dyn↗

arXiv2006

A simple mechanism for controlling vortex breakdown in a closed flow

This work is focused to study the development and control of the laminar vortex breakdown of a flow enclosed in a cylinder. We show that vortex breakdown can be controlled by the introduction of a small fixed rod in the axis of the cylinder. Our method to control the onset of vortex breakdown is simpler than those previously proposed, since it does not require any auxiliary device system. The effect of the fixed rods may be understood using a simple model based on the failure of the quasi-cylindrical approximation. We report experimental results of the critical Reynolds number for the appearance of vortex breakdown for different radius of the fixed rods and different aspect ratios of the system. Good agreement is found between the theoretical and experimental results.

physics.flu-dyn↗