Experimental Investigation of Scour Reduction Around Spur Dikes by Collar Using Taguchi Method

摘要

Scouring around spur dikes, which are popular guide bank structures, is a major concern for hydraulic engineers. Collars are protective palates which are used to reduce the local scouring. Employing an effective collar needs the adjustment of several factors such as shape, area and installation elevation. However, investigating all these factors and their combinations is often neither economical nor feasible. One appropriate approach to overcome these problems is to conduct these experiments based on fractional factorial designs such as the Taguchi method. Therefore, the main objective of the present study is to investigate the effects of different shapes, sizes and installation elevations of the collar to reduce scour around straight and angled spur dikes using the Taguchi method. In the first part of this paper, experimental data were collected based on a Taguchi mixed experiment design (L-18). Then, using Taguchi analysis, the optimal condition for collar efficiency was obtained. In addition, analysis of variances confirmed that the collar elevation, collar area and spur dike angle factors had significant impacts on the scouring depth reduction, while the collar shape proved to be an insignificant factor. In the second part, the validation tests revealed that the Taguchi method achieved high prediction accuracy in the experiments. In the last part, the variation of flow intensity was investigated and the experimental results indicated that by increasing the flow intensity, the collar performance was reduced accordingly.