Chicago Beach Resort Development - A Review of Galloping of Rectangular Prisms Pertinent to the Stability of the Tower Hotel External Frame. G.U. Aero Report 9619

Vezza, M. (1996) Chicago Beach Resort Development - A Review of Galloping of Rectangular Prisms Pertinent to the Stability of the Tower Hotel External Frame. G.U. Aero Report 9619. Technical Report. Department of Aerospace Engineering, University of Glasgow.

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Abstract

In this report a review, commissioned by W.S. Atkins and Partners Overseas, is presented of the factors which determine the high speed galloping stability characteristics of rectangular prisms. The information is subsequently used to make an assessment of the galloping stability of the external frame of the Tower Hotel, a structure which forms part of the Chicago Beach Resort Development. The predictions of linear theory are explained, and the effects of aspect ratio, freestream turbulence and reduced damping discussed in detail. The variety of oscillatory response is explained with reference to both non-linear theory and results from wind tunnel experiments. A number of prevention methods are proposed, based on results from model and full-scale tests. It is concluded that the factors discussed can have a marked effect on the galloping tendency and response of rectangular prisms. Notwithstanding the limitations of the sectional aerodynamic theory employed, an assessment of the transverse galloping stability of the Tower Hotel external frame is made. The added dampers, originally designed to suppress vortex excitation, also play an important role in the suppression of galloping in the upper two bays of the exoskeleton. With these dampers the calculated threshold wind speeds are substantially in excess of those likely to occur in the top two bays, even in extreme conditions. Without the dampers galloping excitation would be possible, especially in low turbulence flows. The lower two bays have higher natural frequencies and mass, and experience lower wind speeds. The corresponding level of damping required may be achievable without dampers. No published data has been found to enable an assessment to be made of the aeroelastic stability of the Tower Hotel mast. Although circular sections do not gallop, very slight deviations from circularity may result in an unstable section. The situation is exacerbated by the lower turbulence intensities at this height, as well as the given slenderness, exposure and fixing arrangements. It is recommended, therefore, that a series of aerodynamic tests be performed to investigate the stability of the mast.

Item Type:Research Reports or Papers (Technical Report)
Status:Published
Glasgow Author(s) Enlighten ID:Vezza, Dr Marco
Authors: Vezza, M.
College/School:College of Science and Engineering > School of Engineering > Aerospace Sciences
Publisher:Department of Aerospace Engineering, University of Glasgow
Copyright Holders:Copyright © 1996 Department of Aerospace Engineering, University of Glasgow
Publisher Policy:Reproduced with the permission of the Department

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