Author(s): Subhasish Das, Ritam Mukherjee, Rajib Das, Asis Mazumdar
Linked Author(s): Subhasish Das
Keywords: Scour, vane angle, flow shallowness, densimetric Froude number, effective scour width
Abstract: Stream bank erosion and deposition in small channels are a major resource management problem to hydraulicians. The channel depth reduces significantly in many open channels due to sediment deposition. This in turn makes it non navigable. Hence, if the sediments could be shifted to one side of the bank of the channel, it may help in navigation. In this study, an attempt is made to check whether the sediment could be transported to one side of the pier i. e. the aim is to increase the scour more importantly the dune downstream, to be non-symmetrical. The present study is an experimental work on scour geometry analysis of a square pier with a vane of varying vane angles, flow depths and discharges. Sixty experiments are carried out using a square pier of 7 cm width with a vane fixed to it on one side at different vane angles of 0� (without vane), 15�, 30� and 45�. For each of the four vane angles, three different approaches of flow depths are tested and for each flow depth, five different discharges experiments are carried out. The differences of scour geometry with and without vane are noted. The scour and the dune are found more on the vane side. The dune is not symmetric. The scour depth is more for higher vane angle whereas lower scour depth is observed for higher flow depth. The scour depth increases with increase in densimetric Froude number, it decreases with increase in flow shallowness or relative inflow depth. Effective flow shallowness is calculated and analysed to determine further scour and sediment transportation characteristics. It is also observed that with the decrease of flow shallowness, more sediment is transported towards the downstream alongside the vane
Year: 2017