Analysis on Analysis of Flow Characteristic at Natural Inclined Weirs in Hydraulic Experiment

Kim Ji-hyun, kim Jong-Tae, Kang Joon-Gu, Lee Nam Joo

Thursday 2 july 2015

12:36 - 12:39h at South America (level 0)

Themes: (T) Water engineering, (ST) Hydraulic machinery and industrial flows

Parallel session: Poster pitches: 11C. Engineering - Industrial

Natural inclined weirs in various shapes and materials are installed in order to restore rivers and develop environmental projects. Inclined weirs can stabilize and protect the erosion of downstream as they have flat slopes compared to a typical round crest weir (RCW). Particularly, inclined weirs, which have environmental effects by aeration and habitat effect caused by their materials, will be applied to river projects after various transformations in the future. However, experiments and flow characteristic analysis on discharge conditions and structural shape of inclined weirs are very restricted. Existing researches were mostly about erosion of diagonal weirs in downstream or scour protection (Bormann and Julien, 1991; Song et al., 1994; Rice et al., 1998; Kim et., 2003). This study first examines the effect of basic inclined weirs then investigates how the various changes in length, width, shape of Crest can affect flow characteristics. A 3D printer was used to make an inclined weirs model (0.4 m × 0.4 m × 0.1 m) for the experiment model in this study, and the experiment was conducted in a water way which is 0.40m in width, 12.0m in length and 0.5m in height. The experiment was conducted in total 8 different discharge conditions (0.00183 m/s3_ 0.01204 m/s3) and various downstream water level condition. By measuring the water level and flow velocity, it was possible to figure out how the occurrence location of critical flow, gage height and Velocity change, change according to the ratio of gate opening changes. This study is an analysis of flow characteristics according to the changes in flow discharge change through hydraulic experiments. Also, it derives the standard coefficient of various shapes of transverse inclined weirs. We were able to reach the following conclusion through this study. The equation for stage-discharge relation curve is y = 0.2827x + 0.1236. The result of hydraulic experiments indicates that the value for basic type of discharge coefficient lies between 0.472 and 0.599.