Author(s): Majid Fazli; Masoud Ghodsian
Linked Author(s): Masoud Ghodsian
Keywords: Spur dike; Flow field; Scouring; 90°channel bend; Bed topography
Abstract: Spur dikes are structures constructed at outer bank of bend to deflect the flowing water away. Most of the previous investigations on the flow behavior and scour around spur dikes were carried out in straight flume. The mechanism of flow and sediment discharge is very complicated, when a spur dike is constructed in a bend. In this research the three-dimensional flow field around a spur dike in different locations under clear water regime was experimentally measured in a laboratory flume with 90 degree bend, using an Acoustic Doppler Velocimetre (ADV) vectrino model. Sand with uniform grain size was used as the bed materials, four locations for spur dike selected in experiments were 30,45,60 and 75 degree in outer bank of bend. Three-dimensional time-averaged velocity components were detected at different horizontal and vertical planes. Flow behavior and flow field characteristics at different locations are considered and compared in this paper. In addition, bed topography was taken in all experiments. Finally, the relations between flow characteristics and scouring have been defined by using the flow field. This investigation will help researchers for better understanding of scouring phenomenon near the spur dikes.
Year: 2009