The wake of a circular cylinder enclosed in various shrouds is experimentally investigated in a wind tunnel at Reynolds number of 7000. The aim of the present work is to understand the effect of different shroud types on the vortex shedding frequency and vortex structures from the shrouded cylinders. The tested shrouds are porous screen cylinders and a circular-holed shroud at various porosities of 37%, 48% and 40%, respectively, with the diameter ratio between the shroud and the inner cylinder of 1.3. Phase-averaged analysis is used to examined the large-scale coherent structures with one hot-wire probe moving across the wake in the y-direction to measure the velocity components and another fixed at y/d=1 to 2 from the wake centerline to provide a phase reference to the measured velocity signals. It was found that the vortex shedding persists to some great distance downstream in the wake of the tested shrouds. While the strength of the coherent structures in the wakes of the bare cylinder and tested shrouds are comparable, those in the circular-holed shroud and screen shroud of 48% porosity are 40% higher than the former two at x/d=10.
- Fluids Engineering Division
On the Effect of Various Shrouds on the Wake of a Circular Cylinder
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Azmi, AM, Zhou, T, & Cheng, L. "On the Effect of Various Shrouds on the Wake of a Circular Cylinder." Proceedings of the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 1B, Symposia: Fluid Machinery; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Flow Manipulation and Active Control: Theory, Experiments and Implementation; Multiscale Methods for Multiphase Flow; Noninvasive Measurements in Single and Multiphase Flows. Chicago, Illinois, USA. August 3–7, 2014. V01BT14A016. ASME. https://doi.org/10.1115/FEDSM2014-22267
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