بررسي تاثير شكل مقطع عرضي پايه هاي استوانه اي بر روند آبشستگي با استفاده از مدل فيزيكي

Investigation of Cross Sectional Shape Effect of the Cylindrical Piers on Scour Process Using a Physical Model

In this paper, the scour process around cylindrical piers due to steady currents has been investigated using a physical model. The cross sectional shape of the piers (circle, ellipse, rectangular and composite), the laying direction of the pier with respect to the flow, the bed sediment particle size, aspect ratio of the length to breadth and also the Reynolds number, were the main variable parameters in this research. The experimental results have been compared with those of the other researchers. The tests have been carried out under clear water conditions and the whole scour process has been monitored. The results of investigations have shown that the cross sectional shape of the piers had great effect on the maximum scour depth, and it reduced up to 30 percent in some cases. Finally, with the knowledge of the different effective coefficients of the scour process a formula has been suggested for estimating the scour depth.