Studying the Effective Length of Crest in Three-side Spillway

Side channel spillways are widely used in dam outlet works for irrigation and drainage networks; and also in water and wastewater facilities. The main hypothesis for the development of multi dimension plan for these spillways has been to increase the transmission capacity by increasing the length of the spillway crest within a certain transverse range. Finding an appropriate geometry for this type of spillway has always been an important issue for the designers of hydraulic structures.In this research, targeting the effective length of the crest of these spillways, numerical modeling of the design of the spillway has been studied. The results indicates that the designed plans with intensified interference area of normal and lateral flows, has shown the largest reduction in the effective length of spillway crest. Also, the spillway model 5, due to possessing just one conflict zone for normal and lateral flows, and also low compaction of falling flow due to long side-arms has been shown as a good sample of the discharge performance.

Keywords:

Three-Side spillways , Effective crest length , discharge coefficient , numerical modeling