Experimental Study to Investigate the Flow Pattern Associated to Angled Groins
Ibrahim M. M.
Shoubra Faculty of Engineering, Benha University P.O. box 11629, Shoubra, Egypt
Abstract: Groins (spur dikes) are structures constructed at an angle to the flow in order to deflect the flowing water away from critical zones. The main objectives of the study are to investigate the hydrodynamic impact of oriented groin existence in a stream bed. A 2-D laboratory flume model was used. About 30 runs were carried out for monitoring the impact of groin length, orientation angle, and the discharge on working length, and velocity components. 28 measuring points were used for velocity measurements distributed as 4 lines from A to D crossed by 7 cross sections. The study showed that the straight groin of 8cm (20% contraction ratio) has the longest working length, however the repelling groin of angle of 600 and 4cm length of (10% contraction ratio) presented the shortest working length. The velocity was decreased than the basic case at the nearest velocity line to groin installation; however the velocity increased than the basic case for the rest lines. The velocity was inversely proportional to groin length upstream and downstream groin location. The impact of groin orientation angle on velocity was exclusive at lines A and B; however the impact was vanished after that at lines C and D. Groin installation proved high efficiency in bank protection especially with high discharges.
[Ibrahim M. M. Experimental Study to Investigate the Flow Pattern Associated to Angled Groins. J Am Sci 2012;8(10):313-322]. (ISSN: 1545-1003). http://www.jofamericanscience.org. 46
Key Words: Groins; Flume Model; Contraction Ratio; Orientation Angle; Working length; Hydrodynamic Impact. Full Text 46