Current Research
Vortex induced oscillations of elongated bluff bodies
For almost 70 years - since the collapse of the Tacoma Narrows Bridge -
there has been an awareness of the inherent flexibility of suspended
long-span bridges. Over these many years, new bridge designs have
been tested in wind tunnels to determine if the design is
aerodynamically sound. There are two fundamental problems with
flexible bridge sections: flutter and oscillations induced by
alternating wake vortices. The collapse of the Tacoma Narrows
Bridge was due to the flutter instability and had nothing to do with
the well known von Karman vortex street. However, the Great East
Belt Bridge in Denmark (which at opening in 1998 was the longest
suspension bridge in the world) did exhibit resonance from alternating
vortices forming in its wake. This would have caused many drivers
to become sea-sick due to the large amplitude, low frequency
oscillations. The bridge had to be retrofitted at high cost by
welding turning vanes onto the bridge to disrupt the aerodynamics of
the forming vortex street.
The current research seeks to use the well-established section model technique in wind engineering to obtain fundamental knowledge about the aerodynamics associated with sections similar in dimension to bridge deck cross-sections. The term 'elongated bluff body' is used to describe these shapes which are typically much longer in the streamwise direction than in the cross-stream direction. Experimental techniques and knowledge developed in the fluid mechanics community will be used and further developed to understand these phenomena. These methods include the use of Time Resolved Particle Image Velocimetry (TR-PIV). The hope is to better understand these phenomena to help optimize bridge designs in the future.
The current research seeks to use the well-established section model technique in wind engineering to obtain fundamental knowledge about the aerodynamics associated with sections similar in dimension to bridge deck cross-sections. The term 'elongated bluff body' is used to describe these shapes which are typically much longer in the streamwise direction than in the cross-stream direction. Experimental techniques and knowledge developed in the fluid mechanics community will be used and further developed to understand these phenomena. These methods include the use of Time Resolved Particle Image Velocimetry (TR-PIV). The hope is to better understand these phenomena to help optimize bridge designs in the future.
Also from this web page:
Zachary Taylor
Contact Info
Western Engineering
BLWTL, Room 146
Telephone: (519) 661-2111 x 88146
