بررسی تاثیر طول سرریز مستغرق بر تغییرات توپوگرافی بستر در خم 90 درجه‌ تند

In this study, the effect of bendway weir length on bed topography of a sharp 90 degree bend was investigated, experimentally. tests are conducted at the hydraulic lab of shahid-chamran university in a 90 degree sharp bend (r/b=2). seven bendway weirs were placed at the outer bank with a height of 5 cm (one-third of flow depth), angel of 30 degrees and three different weir lengths (l/b= 0.15, 0.2 and 0.25), each under four different flow conditions (froude number ranged from 0.137 to 0.3). at the end of each test, bed topography of bend were taken by a laser bed profiler and plotted by surfer. comparison of scour and deposition patterns for different weir length shows that weir with the length to width ratio equal 0.2 provides the lowest volume of eroded bed material.