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Indonesia is currently building many large dams to ensure the water security. One of the projects is Cisokan Lower Dam located in West Java Province of Indonesia. The height of the dam is 98 meter and the spillway is designed with flip bucket type. Downstream scouring became a major concern for the safety of the structure. In order to analyze and e...
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... researchers investigate the downstream scouring impact from the jet force. Scour hole is a determination of many hydraulic parameters such as jet trajectory length, discharge time series, tailwater pool depth, and impact resistance of the riverbed as shown in Figure 1 ( Manso, 2006). Other output research from Vischer and Hager (1995) mentioned that if the ski-jump bucket is not well designed, it may cause severals issues such as energy dissipation by dispersion may be insufficient, impact of the water jet may fall in an improper location, and structural failure of the bucket may occur due to high-pressure. ...
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Citations
... So far, not enough research has been done on the design of these splitters, and in this field, we can look at the research works of Roberts (1943), Mason (1983), Khatsuria (2005), Annandale (2006), Annandale (2006), Safavi et al. (2011), Asadi et al. (2015, Castillo & Carrillo (2016), Movahedi et al. (2018), Zulfan et al. (2019) and a few other studies (Mason & Arumugam 1985;George & Annandale 2008;Asadi et al. 2015;Castillo & Carrillo 2016;George & Annandale 2017;Movahedi et al. 2018;Zulfan et al. 2019). These researchers have focused on providing criteria for the optimal design of the dimensions and layout of splitters. ...
... So far, not enough research has been done on the design of these splitters, and in this field, we can look at the research works of Roberts (1943), Mason (1983), Khatsuria (2005), Annandale (2006), Annandale (2006), Safavi et al. (2011), Asadi et al. (2015, Castillo & Carrillo (2016), Movahedi et al. (2018), Zulfan et al. (2019) and a few other studies (Mason & Arumugam 1985;George & Annandale 2008;Asadi et al. 2015;Castillo & Carrillo 2016;George & Annandale 2017;Movahedi et al. 2018;Zulfan et al. 2019). These researchers have focused on providing criteria for the optimal design of the dimensions and layout of splitters. ...
... Also, no study has been performed on the application of a downstream scour model, and the knowledge available on this topic is negligible. In the current situation, a comprehensive study is required to analyze the scour hole pattern downstream of the overflow spillway, as well as its effects on the free fall jets, and to provide an optimum design for splitter arrangement and dimensions (Zulfan et al. 2019). ...
One of the most effective ways to reduce the water jet erosion power during dam overflow is to use splitters on the lower side of the spillway. The dimensions of scouring holes and their location in the dam basin should be accurately determined. Experimental models and data-driven techniques can be effectively used for estimating the dimensions of scouring holes. The focus of this paper is evaluating the effects of splitters on the downstream scour hole of overflow spillways and providing an optimized splitter configuration. The Support Vector Regression (SVR) method performance in predicting the scour hole dimensions and its location downstream of the dam has been examined using 116 experimental data. In order to evaluate the efficiency of the proposed model, we used different statistical measures. The results show that the presence of splitters decreases the slope of downstream scouring in all situations. It is also shown that the SVR method can accurately estimate the dimensions of the scour hole and its location. HIGHLIGHTS
Designing, constructing and equipping large-scale hydraulic models.;
Development of a simulation model to predict the dimensions of the scour hole in the presence and absence of splitters.;
Using the SVR method.;
Presenting a new approach for designing and studying the splitters as well as the scouring phenomenon.;
Finding the relationship between the scouring phenomenon and its governing parameters.;
The presence of hydraulic jumps downstream of the weir structure is a natural occurrence that indicates a change in supercritical to subcritical flow characteristics. Hydraulic jump is one indicator of the dissipation of energy in the stilling basin. Therefore, the absence of a hydraulic jump can be a problem for some weirs, as happened in the Cikeusik Weir, which experienced damage to the stilling pool floor so that the energy dissipation did not function optimally. This paper will discuss the potential causes of damage to the Cikeusik weir and alternative designs for its countermeasures. A physical model test was carried out in the laboratory with a scale of 1: 40 to obtain an appropriate alternative to the stilling pond design for the Cikeusik weir. The tests were carried out with variations in the discharge Q2 years, Q25 years, and Q100 years, respectively. Three model tests were conducted, namely the existing and two modified designs. Based on the model testing results, extending stilling basin floor length with a dentated end sill and adding downstream riprap is the most optimal alternative because it has an energy reduction effectiveness of up to 80% and the lowest downstream scour potential compared to other options. The results of this test are expected not only to be used as an alternative to mitigate the damage to the Cikeusik weir but also to other locations that have similar problems. Keywords : Cikeusik Weir, stilling basin, Froude number, local scour, physical model
