# Numerical Study of Partial Dam-Break Flow with Arbitrary Dam Gate Location Using VOF Method
## 4 Conclusions  
In this research, the partial dam-break problem with symmetrical and asymmetrical locations of dam gate is exhibited accurately by the VOF-LES model. The effectiveness and robustness of the employed model in performing hydraulic characteristics within reservoirs and flood plains are achieved by using a reference test case from literature. The very good matching between predicted results of water depth, velocity component profiles and flooding map and observed results demonstrate that the presented 3D CFD model precisely predicts discontinuous, turbulent flow.  
With a variety of initial stages and breach sizes, as well as two locations of partial dam failure, in 18 models, some novel numerical investigations of dam-break flow in early stage were discovered in this research and are listed below:  
* Increasing breach size causes reducing water depth profile at the central line of the dam gate on a reservoir. The opposite trend is observed in depth-average velocity hydrographs.
* Velocity and vorticity components in \(x\) and \(z\) directions are independent of the position of dam gate. In contrast, components \(v\) and \(w_{y}\) in the \(y\) axis vanished when the reservoir outlet was at the central line of the dam.
* Streamline patterns exhibit the movement of fluid particles at certain times. In early stage, not all fluid elements move to the reservoir mouth when breach size is small.
* Some sophisticated hydraulic factors indicating swirling flow are involved in the time series of \(q\)-criterion and vortex core mapping. In the case of symmetrical reservoir outlet, breach width increases, vortex core area at both corners near the dam site decreases, which means vorticity is weak. In contrast, stronger swirling flow appeared  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \(\mathbf{N}^{c}\) & \(h_{0}\) (cm) & **b/B (–)** & \(\eta\)**–**Schoklitsch (–)** & \(\eta\)**–**3D, A (–)** & \(\eta\)**–**3D, B (–)** \\ \hline
1 & 20 & 0.084 & 0.5505 & 0.5140 & 0.5720 \\
2 & 20 & 0.168 & 0.4629 & 0.4899 & 0.4924 \\
3 & 20 & 0.251 & 0.4183 & 0.4363 & 0.4379 \\ \hline
4 & 40 & 0.084 & 0.5505 & 0.5568 & 0.5785 \\
5 & 40 & 0.168 & 0.4629 & 0.4626 & 0.4947 \\
6 & 40 & 0.251 & 0.4183 & 0.4185 & 0.4531 \\ \hline
7 & 60 & 0.084 & 0.5505 & 0.5975 & 0.6239 \\
8 & 60 & 0.168 & 0.4629 & 0.4801 & 0.5095 \\
9 & 60 & 0.251 & 0.4183 & 0.4291 & 0.4638 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Peak discharge.  
Figure 17: Comparison between analytical results with numerical ones.  
near the top right corner of the reservoir when a broken block is asymmetrically placed. * Normal peak discharge does not only depend on initial water stage, and dam breach ratio. It is also influenced by location of dam gate. The reservoir's initial water stage is greater, and maximum flow rate released by symmetrical breach location is more notable, than those released by the asymmetrical case. The selected model indicated high accuracy and clarity in performing several 3D hydraulic characteristics of partial dam-break flow. It is also extremely straightforward in providing a wide range of options for geometry of computational domain and initial conditions.  
Conceptualization, T.T.H.L.; Methodology and writing, T.T.H.L.; Formal analysis, T.T.H.L., V.C.N.; Simulation, T.T.H.L., V.C.N. All authors have read and agreed to the published version of the manuscript. This research received no external funding.  
Data Availability StatementData sharing not applicable.  
The authors declare no conflict of interest.