The mean characteristics of horseshoe vortex at a cylindrical pier

The primary horseshoe vortex formed in front of a cylindrical pier and believed to be the prime agent responsible for scour has been investigated experimentally during the entire process of scouring. A simple and effective method was employed to obtain the time-averaged characteristics of the vortex in terms of parameters relating variables of flow, pier and the channel bed. An expression for the maximum equilibrium scour depth has also been developed from the vortex velocity distribution inside scour hole. The resulting scour prediction equation has been found to give better results compared to the results of well-known predictor models when applied to model scour data.