Research on Flood Discharge and Energy Dissipation of a Tunnel Group Layout for a Super-High Rockfill Dam in a High-Altitude Region
Round 1
Reviewer 1 Report
The subject of the paper is interesting, and the data obtained from the experimental tests are valuable. However, the document is not a scientific paper, but a case study or technical note, and has serious deficiencies:
- The effect of high altitude on water energy dissipation at super-high rockfill dams is the most original subject. However, it is not well explained and is treated
- Data management should be improved.
- The document, both in text and in figures, requires a great deal of improvement to reach the necessary quality standard for publication in a scientific journal.
Going into detail, the following comments might help to improve the paper:
- The writing of the paper and the quality of the figures should be improved throughout the paper.
- Although my use of English is not advanced, my impression is that English should also be greatly improved.
- Line 54 -. A longitudinal profile is necessary to properly understand the explanation.
- Lines 60-80. Figures or sketches of the cited cases would increase the clarity of the explanation.
- Lines 106-108. Cite the “few studies on flood discharge…”.
- Lines 123-126. Write the equations out of the text.
- Lines 142-143. The chosen scale should be justified. Also, a discussion about the scale effect should be included in the discussion section.
- The way flow pattern was defined must be clearly explained. Furthermore, a detailed description of the instrumentation should be added. The precision and frequency of the pressure gauges are important data.
- Table 1. The very high scaled velocities might be greatly reduced in the prototype due to the flow aireation. It would significantly affect the impact point. Also,
- Table 1. How was the nappe width measured?
- Lines 204-214. It would be clarifying to discuss the influence of the measured pressures in the safety of the stilling basin, and why a reduction is needed.
- Figure 7. Differentiate clearly what is original and modified.
- Table 3. It would be appreciated to include the percentage of reduction in pressures related to the original design.
- Line 284. The influence of the high altitude is a central point of the paper, and the quantification of this influence must be clearly justified with detail. How did you calculate the given quantities?
- Figure 11. Must be enhanced (also the rest of the figures) and clearly explained.
- Figure 18. Where is the origin? Explain that clearly.
- Lines 385-389. Detail the calculation of the energy dissipating rate.
- Line 400. Conclusions should be written more clearly and in a better style, the same as in the rest of the paper.
- Lines 406-407. Quantify the “effective energy dissipating” and justify why it is “insufficient”.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript is a description of an elaborate and very detailed description of a research/experimental flood discharging and energy dissipating tunnel of super-high rockfill dam in China. The authors have executed the experiments in high detail and with scientific soundness. However, they have prepared their manuscript as a report for the authorities for the dam, rather than in a typical manner of a research article.
My major concern is related to this problem. The authors do not present the broader context of problems they try to solve with their research in a structured manner. They do not discuss what we know from the literature so far and do not clearly state the objective of this study.
Then after presenting their results they do not compare with other findings of the literature, presenting the pros and cons of their approach, its novelty and its importance.
Most importantly the authors do a poor job to put the study and the findings in the context of a research problem which first has to be presented. The Discussion and Conclusions sections should compare and discuss the results and their interpretation in the context of previous literature findings.
- The manuscript starts very abruptly. The meaning of the Introduction section is to allow the authors to introduce the problem to the reader. The authors should improve the very start of the study with introductory statements.
- The authors have included a lot of details of the dam in the Introduction section. They should transport these details to the following section (section 2). According to the journal’s instruction for authors “introduction should briefly place the study in a broad context and highlight why it is important. It should define the purpose of the work and its significance, including specific hypotheses being tested. The current state of the research field should be reviewed carefully and key publications cited.” The authors have deviated a lot from the above description.
- Future research directions should be also mentioned possibly in the Conclusions section
- The language needs extensive revisions
- L43 the term “high cold” needs re wording. It is not very common.
- L103-105 please reword the terms domestic and foreign scholars.
- L108-110 The phrase “Combined with Rumei hydro- power station in Tibet, this paper explores the optimal layout scheme of water release structures of ultra-high rockfill dam tunnel groups in high altitude areas” is not clear please reword.
- There should be a location map to present the location of the Dam
- Figure 4 and Figure 9 are somewhat repetitive. Please justify why it is necessary to show again.
- Figure 17 needs larger fonts. Not easy to read the numbers.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I apreciare that the authors have greatly improved the manuscript. However, some additional improvements must be done in order to achieve the quality level for publication in a scientific journal. Some comments are also included below.
- The quality of figures must be enhanced. For example, different line width must be used for main and auxiliary lines, numbers and lines should not overlap, low quality figures must be redrawn, etc.
P1; L33: Energy dissipation rate is scarcely improved.
P3; L16-18: It looks there is a contradiction in the phrase. Modify or explain that.
P5; L84: Please, justify with a reference that “the Weber number of the flow surface in the model is required to be WE>500”.
P5; L185: Please, include the way you calculated that “WE is about 750”.
P5: L186-187: Please, justify why “the scale effect has little impact on these”. It is not obvious.
P6; L204: Please, describe how “the flow pattern is photographed”.
P6; L209-: A figure with a sketch of the way you measured the width of the nappe would clarify the explanation.
P9; L277-: Please, describe clearly the way you estimated the energy dissipation area and the power per unit water volume.
P10; L322-323: Revise the phrase. It looks like there is a mistake.
P11; L358: What is DL/T5166-2002? I Think you should include this as a reference.
P12; L369-: Please, justify the estimated values.
Figure 19: What do you mean by fluctuating pressure?
P19; L549: Include units of 259.82.
P19; L549: Please, justify why you chase 110m.
P19; L555-556: Differences are not relevant.
P19; L576: Please, include the calculation related to atomization.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 2 Report
The authors have addressed all the remarks and concerns, changing a great deal of the manuscript improving it greatly in the direction of addressing my concerns. I therefore suggest that the manuscript is fit to be published in its current form in the journal.
Author Response
Thank you very much.
Round 3
Reviewer 1 Report
I include some comments under some of your answers, in order to improve the manuscript:
- The quality of figures must be enhanced. For example, different line width must be used for main and auxiliary lines, numbers and lines should not overlap, low quality figures must be redrawn, etc.
Response to comment: We have made minor adjustments to the figure. Because there are many lines and the thick and thin lines cannot distinguish the structure, we mainly use different color lines or filling to clearly distinguish the structure. We hope to get your approval.
REVIEWER: In really think that quality of figures based on plans is not enough for publication and must be redrawn.
- P1; L33: Energy dissipation rate is scarcely improved.
Response to comment: Because the total energy is very high, the energy dissipation of hydropower projects with high head and large energy is a difficult problem. We must try our best to increase the energy dissipation rate by 0.8% relative to the total energy of 259.82m. The energy of more than 200m head will not be eliminated and will be released to the downstream, which will cause serious losses to the downstream river channel and people's lives and property. However, increase the energy dissipation rate by 0.8%, 259.82 * 0.8% = 2m, and increase the energy dissipation rate by 2m, At the same time, the flow velocity decreased from 9.67m/s to 6.92m/s, which is obvious. The flow velocity in the downstream channel of 6.92m/s has reached the safe flow velocity. Therefore, the effect of increasing the energy dissipation rate of 0.8% is very good.
REVIEWER: I agree that reduction of the velocity is significant. Please, include this explanation in the manuscript.
- P6; L204: Please, describe how “the flow pattern is photographed”.
Response to comment: When the discharge is stable, we take photos of the flow in the plunge pool, and then compare and analyze the flow pattern photos under different working conditions. See Figure 6\11\14.
REVIEWER: Water is transparent, but there are different techniques for obtaining the flow pattern. Please, describe precisely the technique used. Were the bubbles the key for following the trajectory? Another technique?
- P9; L277-: Please, describe clearly the way you estimated the energy dissipation area and the power per unit water volume.
Response to comment: The maximum flood discharge power borne by the stilling basin of the flood discharge system of RM Hydropower Station under the check condition is 31000mw, and the depth of the plunge pool is 64.6m. In the design scheme, the effective energy dissipation area in the plunge pool is 15,185 m2(See Figure 9), which is only about one-fifth of the total area of 74,109 m2. The calculated maximum energy dissipation power per unit water volume is (31000×1000)/(15185×64.6)=31.60 kW/m3.
REVIEWER: Please, include a complete explanation of this in the manuscript.
- P12; L369-: Please, justify the estimated values.
Response to comment: We have conducted several groups of tests under different air pressures with different pick angles, used several of them to couple the calculation correction formula of pick distance under low air pressure, and verified the correctness of the formula with the remaining groups. Then calculated K0, K1 and K2 according to formula (2) (3) according to the pick distance obtained from the test under atmospheric pressure, and then substituted K0, K1 and K2 into formula (1) to get the flip distance under low pressure, which is corresponding to the flood discharge system of RM power station.
REVIEWER: Please, include a complete explanation of this in the manuscript.
- Figure 19: What do you mean by fluctuating pressure?
Response to comment: Hydrodynamic pressure is a random process of continuous fluctuation. The time average pressure reflects the average force of hydrodynamic water in the measurement period, and the flow force fluctuating up and down around the time average pressure is the fluctuating pressure.
REVIEWER: I am aware of that, of course. Please, define precisely the value “fluctuating pressure”. Is it the difference between maximum and minimum?
- P19; L549: Please, justify why you chase 110m.
Response to comment: In the test, the calculation section is selected at 110m because the flow pattern and velocity of the downstream channel basically do not change much from 110m downstream of the plunge pool, the energy dissipation is basically completed, and the flow pattern of the conventional channel is restored. 110m is not a fixed value, but determined according to the test results.
REVIEWER: Please, include this explanation in the manuscript
P19; L576: Please, include the calculation related to atomization.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 4
Reviewer 1 Report
Thank you for improving the manuscript. It can be published now, in my opinion.
