ELFT HÍRADÓ

[Károlyi György <karolyi AT reak.bme.hu>]

Meghívó Prof Kerry Hourigan előadására

Időpont: október 3. 14:15
Helyszín: BME D épület 316 B terem.

The rich wake transitions of spinning cylinders

Prof Kerry Hourigan, Monash University, Melbourne, Australia

Abstract
Airfoil geometries are used for aircraft wings (and seacraft sails)
because they provide high lift, low drag and little vortex shedding,
leading to stable motion. A non-rotating cylinder has zero mean lift,
high drag and can suffer severe vortex-induced vibrations -- however,
increasing the spin rate of a cylinder leads to high lift, low drag,
with vortex shedding disappearing; the Magnus effect can be used to
advantage in Flettner rotor sails and wings. The 2d and 3d wake
transitions for a cylinder in a uniform flow as its spin rate is
increased have been investigated both numerical and experimentally.
It is found numerically and experimentally that a remarkably rich
array of two- and three-dimensional transitions occurs in the wake
for low Reynolds number. Surprisingly, very large flow-induced
vibrations can occur for an elastically mounted spinning cylinder,
even when the vortex shedding is suppressed.

Some Recent References:

Rao, A., Leontini, J., Thompson, M.C., Sheridan, J. & Hourigan, K.,  A
review of rotating cylinder wake transitions, Journal of Fluid and
Structures, in press.

Borguet, R. & Lo Jacono, D., Flow-induced vibrations of a rotating
cylinder, Journal of Fluid Mechanics, 740, 342-380, 2014.

Rao, A., Leontini, J., Thompson, M.C. & Hourigan, K.,
Three-dimensionality in the wake of a rotating cylinder in a uniform
flow, Journal of Fluid Mechanics, 717, 1-29, 2013.

Rao, A., Leontini, J., Thompson, M.C. & Hourigan, K.,
Three-dimensionality in the wake of a rapidly rotating cylinder in
uniform flow, Journal of Fluid Mechanics, 730, 379-391, 2013

Radi, A., Thompson, M.C., Rao, A., Hourigan, K. & Sheridan, J.,
Experimental evidence of new three-dimensional modes in the wake of a
rotating cylinder, Journal of Fluid Mechanics, 734, 567-594, 2013.