بررسي آزمايشگاهي تاثير شعاع انحناي قوس 90 درجه بر تغييرات توپوگرافي بستر

Experimental investigation on the effect of curvature of bend on bed topography in 90 degree bend

Rivers are main sources of water supply. Recognition of rivers behavior and their changes, particularly in Curved channels, is critical. In this paper, results of experiments on scour pattern in a 90 degree bend are discussed. Experiments have been carried out in a channel with three different radiuses of curvatures, including mild, moderate and steep. Bed topography has been measured by Laser Bed Profiler. Comparison between different lateral sections, longitudinal sections and bed topography has been made and scouring pattern is analyzed. The results indicate that reduction of radius of curvature of the bend leads to increase of bed topography changes and sedimentation and scouring rates. Also, scour can be seen along downstream straight channel and near the outer bank; however, this is more evident in the steeper bend.