Study of energy dissipation in the chute with submerged obstacle using physical model

As a method for dimension reduction and elimination of energy damper structures that are located downstream of rapids, obstacles that are put on rapids are sometimes employed. In this research, damping capabilities of floating cubic obstacles were investigated using an experimental model. To do this, various experiments were performed on four different slopes of rapids with and without obstacles in a laboratory open channel in the hydraulic laboratory of Shahid Chamran University of Ahvaz. Results of the experiments without obstacles on discharges contained in this research’s scope showed that the amount of damped energy relative to the upstream energy ranges from 10 percent for a slope of 1:4 to 63 percent for a slope of 1:5. According to comparison of energy loss in different slopes, we can conclude that the reduction of chute bed slope increases the relative damped energy. We can also argue that the reduced chute bed slope leads to a slower energy loss procedure. Energy dissipation had an increase of 17 to 44 percent according to the studied results of models with and without obstacles. According to comparison of energy loss in different slopes of models with obstacles, we can conclude that the amount of relative damped energy increases and the damped energy reduction occurs on lower slope by reducing the chute bed slope. Using multi-variable regression, some equations were extracted in the final section in order to predict energy damping in such rapids with or without obstacles.