## 5 Conclusions  
The use of TCC is an effective and practical method to raise the RWT in thermal stratified reservoirs. To provide the theoretical basis for the engineering application of TCC, experimental tests are carried out, whose results fully demonstrated the effectiveness of the TCC in increasing the RWT. For its further research, a 3-D numerical hydrodynamic and water temperature model is built with the same size of the physical model, whose accuracy is verified through comparing with experimental test results. In contrast with previous simulations of TCC, this study describes an arc-shaped curtain, which is closer to reality. Then the influences of different factors on increasing the RWT are studied. According to the analysis of experimental tests and numerical simulation, the conclusions are summarized as follows:  
1. The regulating effects of TCC on the RWT is closely related to the temperature structure of waters. In S1 distribution, the maximum temperature increased by up to 8.3 \({}^{\circ}\)C, while this is only 3.5 \({}^{\circ}\)C under the S2 distribution. 2. The \(CP\) has a little difference on RWT, the position of TCC should be determined after considering the complex terrains, economic condition, waterway transport, and other specific cases in actual engineering. 3. The \(Pr\) directly affects the vertical range of water entering the discharge water. As the \(Pr\) increases, more upper, high-temperature water flows to the downstream of TCC drawn by the force of outlet. But there are critical values of \(Pr\): When the value is out of the range 90%-65%, the impacts of \(Pr\) on RWT is negligible. When the water is released by spillway, variation of \(OSD\) has little effect on the thermal stratification of the forebay, which causes little impact on improving RWT. 5. The change of \(RQ\) has a great influence on the flow field, and reduces the time that the forebay water takes to reach stability. But the effect of \(RQ\) on RWT is small; thus, in practical engineering, the variation of \(RQ\) can be decided by other complex factors and will not influence the improvement effect of RWT. Based upon the above conclusions, the following principles are proposed for the application of TCC in thermal stratified reservoirs. The position of the curtain should be decided with comprehensive consideration of complex terrains, economic condition, waterway transport, and other specific cases. In spring and summer, maximize the \(Pr\) of the TCC to achieve the best effect on RWT without influencing the flow, and increase the \(RQ\) of the water to achieve the final (raised) RWT as soon as possible. The change of \(OSD\) and \(RQ\) can be decided by actual demand, which will not influence the effect of TCC on improving RWT. For those thermal stratified reservoirs troubled with the problem of RWT, the application of TCC is an effective solution. Meanwhile, there are many points worth further study. For example, the paper is carried out based on a model with the generalized topography and temperature structure; the influence of real terrains on RWT should be studied in future. In addition, in winter, some reservoirs have the problem of high-temperature of released water, which is the opposite of our focus; the feasibility of TCC's in this condition is worth researching. Furthermore, the impact of secondary flow on wall-bounded turbulence have obtained some achievements [37], and the role of data uncertainties in identifying the logarithmic region of turbulent boundary layers have been researched [38]; the further research on the secondary flow's impact on the flow field of reservoir within TCC can be expected. The research results presented herein, as well as those of future research for more complex terrains and construction methods, will offer powerful support for the application of TCC to regulate the RWT. All the authors made contributions to the concept and design of the article. Conceptualization, J.L. and Y.Y. ; methodology, W.H. and N.S. ; software, P.L. and W.H. ; validation, J.L. ; formal analysis Y.Y.