Clear Water Local Scour Around Eccentric Multiple Piers to Shift the Line of Sediment Deposition

Article type: Research Article

Authors: Das, Rajib | Khwairakpam, Padmini | Das, Subhasish | Mazumdar, Asis

Affiliations: School of Water Resources Engineering, Jadavpur University, Kolkata – 700032, India

Note: [] Corresponding author: E-mail: rajibdas79@yahoo.co.in

Abstract: Local scour around pier groups has been studied experimentally in clear water scour conditions under different Froude numbers (F_r) and pier spacing. Tests used piers of 5 cm diameter placed at different arrangement and spacing (S) in a sand bed of mean particle size d_{50} = 0.365 mm. For tests on three-piers, piers were arranged in a staggered manner. Two-piers were arranged in line with the flow and one was eccentric pier. The scour depth around all the piers in each group was measured and the bed scour profile for each test has been also prepared. For two-piers experiment arranged in line with the flow, it has been observed that the scour depth increases with closer spacing between the piers for the same Froude number. For closer spacing of piers, the scour holes overlapped with each other. In case of three-pier tests, it was observed that the scour volume was more for 3b eccentricity than 2b eccentricity (where b = pier diameter) and the sediments removed from around the pier group was deposited downstream, more on the side of the eccentric pier.

Keywords: Local scour, pier, eccentric pier, scour depth, scour volume

Journal: Asian Journal of Water, Environment and Pollution, vol. 11, no. 3, pp. 47-54, 2014