Vortex shedding on bridge piers

Abstract

[Abstract]: The phenomenon of vortex shedding from bridge piers has been examined. A review of current literature was conducted in order to assess bridge design principles aiding in reducing the effects of vortex shedding. Experiments were conducted at the University of Southern Queensland’s hydraulics laboratory. The velocity profile downstream of model bridge piers was measured in order to observe the changes to flow caused by a bridge pier under in finer detail.A range of model piers were used in the experimentation. The diameter and surface roughness of the models were altered. Model piers of 20mm, 43mm, 65mm and 90mm were tested. The 65mm model pier was tested with surface roughness heights of 0.03mm, 2mm and 5mm. An Acoustic Doppler Velocimeter and the associated data collection software was used to capture the velocity field downstream of the models. These velocities were used to determine the conditions favourable to the onset of vortex shedding. The recorded velocities were imported into MATLAB for processing and plotting. From the results the relationship between the Strouhal number and Reynolds number was assessed and compared with published data. The results were found to be in accordance with published results. The dimensionless Reynolds number for a body in flow was used to relate the occurrence of vortex shedding on the bridge models to actual piers. It was found that vortex shedding occurs within a wide range of Reynold’s numbers (300 to 10,000).