# SWE-SPHysics Simulation of Dam Break Flows at South-Gate Gorges Reservoir

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. SWE-SPH Principles and SWE-SPHysics

## 3. Model Validations

#### 3.1. Dam Break Flow Interaction with a Triangular Hump

#### 3.2. Dam Break Flow Interaction with a Rectangular Obstacle

#### 3.3. Sensitivity Analysis of the Model

#### 3.3.1. Model Convergences with Different Particle Spacing

#### 3.3.2. Comparisons with Other Numerical Modeling Results

#### 3.3.3. Evaluations on the Particle Splitting Technique

## 4. Model Applications in Engineering Field

^{2}. The dam height measures at 37.5 m and the length of dam is 467 m. The reservoir has a storage capacity of 18.4 million m

^{3}, which serves the downstream area of 1200 km

^{2}with a population of 240 K. Since the reservoir was initially put into operation in 1983, dam leaking has always been an issue. It is estimated that the average leaking rate is around 0.7 m

^{3}/s, which accounts for 46% of the annual run-off into the reservoir. This is not only a waste of water resources but also poses a potential threat to the safety of the dam. To partially relieve the problem, the reservoir has been operated under the designed low water level at $\nabla $2760 m for most of the years. In spite of this, quite a few local collapses have been found on the left shoulder of the dam. The dimension of the collapsed caves could reach as large as 2 m in diameter. These constitute a serious threat to the safety operation of the dam. The South-Gate Gorges Reservoir and Dam are located in the upstream area of Xining, the capital of Qinghai and also many key agricultural sites, so any scale of dam break could cause significant losses to the local economy [24]. To evaluate potential dam break hazards and take relevant engineering measures to combat the disaster, it would be useful to carry out virtual dam break simulations in this area. A site photo including the reservoir, dam and immediate downstream area with points of interest is shown in Figure 13. The hydraulic dam site is located at 36°57′55.54″ North Latitude and 101°53′27.59″ East Longitude.

^{3}/s to 140,000 m

^{3}/s from the full breach to 80% breach, while it only further reduces to 90,000 m

^{3}/s for the 60% breach ratio. This implies that full breach of the dam is the worst scenario in dam break disasters.

## 5. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

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**Figure 1.**Schematic layout of dam break flow experiment with a triangular hump [19].

**Figure 2.**Time histories of dam break flow surface profile at gauging points between experimental data [19] and SWE-SPHysics modeling results at: (

**a**) G4; (

**b**) G10; (

**c**) G13 and (

**d**) G20.

**Figure 3.**Spatial and temporal evolutions of the dam break flow surface profile at time: (

**a**) t = 5.4, 7.4 and 9.0 s; and (

**b**) t = 24.4, 27.0 and 35.4 s.

**Figure 4.**Schematic layout of dam break flow experiment with a rectangular obstacle [21].

**Figure 5.**Time histories of dam break flow surface profile at gauging points between experimental data [21] and SWE-SPHysics modeling results at: (

**a**) H2; and (

**b**) H4.

**Figure 6.**Velocity fields of dam break flow at different stages: (

**a**) t = 0.74 s; and (

**b**) t = 1.76 s.

**Figure 7.**Time histories of dam break flow surface profile at gauging points for three SWE-SPHysics modeling results on [19] at: (

**a**) G4; (

**b**) G10; (

**c**) G13; and (

**d**) G20.

**Figure 8.**Time histories of dam break flow surface profile at gauging points for three SWE-SPHysics modeling results on [21] at: (

**a**) H2; and (

**b**) H4.

**Figure 11.**Area of particle splitting for dam break case [21], coordinated from (0.75, 0.2) to (0.8, 0.8).

**Figure 12.**Time histories of dam break flow surface profile at gauging points computed by using particle refinement and splitting technique at: (

**a**) H2; and (

**b**) H4.

**Figure 15.**Flood maps at t = 600 s after the dam break for different breach ratio conditions: (

**a**) 60%; (

**b**) 80%; and (

**c**) 100%.

**Figure 16.**Flow velocity fields under breach ratio 100% at different time instants: (

**a**) t = 200 s; (

**b**) t = 400 s; and (

**c**) t = 600 s.

**Figure 18.**Spatial variations of (

**a**) water surface; and (

**b**) velocity profile along the central streamwise direction of dam break flow, for different breach conditions.

**Figure 19.**Spatial variations of (

**a**) water surface; and (

**b**) velocity profile along the central streamwise direction of dam break flow, for different particle spacing.

**Figure 21.**Digital inundation photos for two key downstream sites: (

**a**) Gelong Village; and (

**b**) Xiatai Village.

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**MDPI and ACS Style**

Gu, S.; Zheng, X.; Ren, L.; Xie, H.; Huang, Y.; Wei, J.; Shao, S.
SWE-SPHysics Simulation of Dam Break Flows at South-Gate Gorges Reservoir. *Water* **2017**, *9*, 387.
https://doi.org/10.3390/w9060387

**AMA Style**

Gu S, Zheng X, Ren L, Xie H, Huang Y, Wei J, Shao S.
SWE-SPHysics Simulation of Dam Break Flows at South-Gate Gorges Reservoir. *Water*. 2017; 9(6):387.
https://doi.org/10.3390/w9060387

**Chicago/Turabian Style**

Gu, Shenglong, Xianpei Zheng, Liqun Ren, Hongwei Xie, Yuefei Huang, Jiahua Wei, and Songdong Shao.
2017. "SWE-SPHysics Simulation of Dam Break Flows at South-Gate Gorges Reservoir" *Water* 9, no. 6: 387.
https://doi.org/10.3390/w9060387