An Experimental Study on the Dissipation Effect of a Baffle Downstream of a Weir

This study is an experimental study to analyze the dissipation effect of a baffle shape installed to reduce the scour problem downstream of a weir. The hydraulic experiment on the flow dissipation effect created by baffle installation was an experiment under a fixed bed condition to investigate the flow dissipation effect based on changes in flow in the apron downstream caused by?changes in baffle shape. The experimental analysis was conducted by measuring the flow rate at the apron downstream with and without the installation of a baffle on the basis of the flow dissipation effect. This experiment compared the flow dissipation effect achieved with five baffle shapes to analyze the effect of the baffle shape. Two conditions of flow rate were considered: when a water level in the area of super-critical flow was lower than the baffle height, and when it?flowed over the baffle. Overall, the flow dissipation effect was found to be?good when a square baffle with a large flow blocking area was used. The analysis also found that hydraulic jump was facilitated when the front part of the baffle was inclined, as flow was induced to the upper direction. The result of the experiment showed that when performing flow dissipation through the use of a baffle, the effect of flow blocking and flow duration alteration should be considered.

Experimental Study on Stability of Levee Protection Method

For the retaining wall and technologies to protect river levee, many patents were applied and numerous new technologies were developed according to the installation method and material. This study installed a magic retaining wall block, which was developed as new technology product to protect river levee from running water, in actual size experimental water channel and evaluated the hydraulic performance and the stability of technology based on the increase in the flow velocity and discharge by steps. This study divided the experiment into a total of six steps and conducted it accordingly. According to the experiment results, there was no deformation of the surface of the magic retaining wall block or any soil loss at the bottom either, under the condition of maximum flow velocity of 5.37 m/s (discharge of 7.40 m3/s). To analyze the occurrence of scour and the possibility of soil loss at the bottom of a structure due to a high flow velocity, this study conducted an image analysis of Case 6 under the condition of maximum discharge, using a drone. According to the results of an analysis through the drone, there was no soil loss or flow change due to a scour at the bottom of the magic retaining wall block. The results of this study will serve as references in designing a technology applying a magic retaining wall block, and present the methods and procedures to evaluate and verify the development of any further new technology.

Effective Analysis by Arrangement of Multi-Baffle at Weir Downstream

The purpose of the study is to analyze the reduction effects of multi-baffle installed for improving the scour issue of weir downstream and the study reviewed the flow reduction effect for the location of the battle and the reduction effect associated with the baffle installation. We carried out nine cases of experiments and analyzed reduction effects through the flow rate comparison for the arrangement type of the cases. As the result of the experiment, the maximum flow rate in the weir downstream of the case 1, which has no baffle installation, is measured at 2.068 m/s due to multidirectional flow and crossing waves, and channel walls had whirlpool generation on the left and right with fast discharge flow. The maximum water level showed lower water level than when the battle was installed as there is no flow resistance. The maximum stream velocity in the weir downstream from cases 2 to 9 installed with a baffle demonstrated reduction in the maximum stream velocity than before the battle was installed and showed an increased tendency than before the baffle was installed as the maximum water level is affected by flow resistance. As the result of the comparison of the reduction effect by installing the baffle, the V type of the case 6 demonstrated the best reduction effect.