Open Collections

An experimental study of the aeroelastic instability of rectangular cylinders

University of British Columbia

Dynamic wind tunnel tests were made on plunging rectangular cylinders with various depth to width ratios (b/h) and the results were compared with predictions based on the quasi-steady approach. To restrain the models to plunging oscillation they were attached, top and bottom, to transverse shafts guided by hydrostatic air bearings. An electromagnetic eddy current damping device was developed to obtain accurately calibrated viscous damping. Dynamic displacements were measured with a variable coupling electromagnetic transducer designed specifically for this apparatus. Direct force measurements were made for the square cylinder to obtain the lateral force variation with angle of attack in the Reynolds number range of the dynamic tests. The velocity-amplitude curves for those cylinders which oscillated are presented. The curves for b/h = 1.00 agreed with the predictions of the quasi-steady approach, and could be reduced onto one curve by using the ratios of applied damping. The longer rectangles did not prove to be amenable to analysis by the quasi-steady approach, and appeared to be strongly influenced by the instantaneous wake geometry. Rectangular cylinders of b/h over 4.00 did not plunge. Hot wire measurements showed that the Strouhal frequency was present in the wake of the plunging cylinder, occurring simultaneously with the plunging frequency.

Text

2011-11-10

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

http://hdl.handle.net/2429/38938

Mechanical Engineering

University of British Columbia

Graduate