TABLE OF CONTENTS Vibration of significant magnitude may be induced by wind in a wide variety of structures including buildings, television and cooling towers, chimneys, bridges, transmission lines, and radio telescopes. No structure exposed to wind seems entirely immune from such excitation. The material presented here describes several mechanisms causing these oscillations and suggests a few simpler approaches that may be taken in design to reduce vibration of structures induced by wind. There is an extensive literature [1] [2] [3] [4] [5] giving a more detailed treatment of the subject matter.
[1]Davenport, A. G., et al.: New Approaches to Design against Wind Action, Faculty of Engineering Science, University of Western Ontario (unpublished).
[2] Proc. IUTAM-IAHR Symp. Karlsruhe, 1972.
[3] Proc. Conf. National Physical Laboratory, Teddinton, Middlesex, 1963.
[4] Proc. Intern. Res. Seminar, Ottawa, 1967.
[5] Proc. 3d Intern. Conf., Tokyo, 1971.
The types of structure referred to above are generally unstreamlined in shape. Such shapes are termed bluff bodies in contrast to streamlined aeronautical shapes discussed in Chap. 29, Part III. The distinguishing feature is that when the air flows around such a bluff body, a significant wake forms downstream, as illustrated in Fig. 29.15. The wake is separated from the outside flow region by a shear layer. With a sharp-edged body (such as a building or structural number) as in Fig. 29.15, this shear layer emanates from the corner.With oval bodies such as the cylinder in...
