Investigation on the Cavity Backwater of Chute Aerators under Various Atmospheric Pressures
Round 1
Reviewer 1 Report
Parametric experimental study, the relevant parameters of backwater were measured under various atmospheric pressures, including the jet length, cavity subpressure, backwater depth and net cavity length.
The case is characterized Froude Number of the approach flow on different atmospheric pressure conditions and Reynolds number. However, Reynolds number is not defined – what is the typical length – step height or what?
In principle, the flow is fully determined by the dimensionless parameters as Reynolds and Froude numbers and the vacuum degree etam. Maybe Euler number or pressure coefficient are missing in the analysis? In this context, the step height “h” is the redundant parameter to distinguish between the cases – see Tab.2 and it is irrelevant. The dimensionless parameters should be considered as variables and dependence on Fo and Re should be studied.
Notes:
- Hydraulic model
The geometry is not well defined, in Fig. 1a. Where is “aeration step height d”? What is the “chute slope i” definition?
l.99 V0 was measured? How?
Fig.2a on y-axis there is L/h, should be Lmax/h. The graph with Fo on x-axis would be more explanatory.
l.160 show “emergence angle theta” in Fig.1
l.164 and Fig.2b what is the fiL? Give it a name and physical meaning.
Fig.3a please put into the graph the lines representing the formula (2) for the given cases.
Fig.3b there is air speed in the shaft Va. How it is evaluated, should be described. Show Va in Fig.1.
Fig.4 the photos are not of adequate quality, no quantitative conclusions could be drawn. Indicate Lnet in figures.
l.334 explain physical meaning of the T.
l.397 Notation, physical dimensions should be given. Not all quantities are there, some are missing.
- Conclusions are too general, the results should be commented, effect of vacuum in particular.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
This experimental study focuses on the investigation of critical physical properties of the cavity backwater induced by chute aerator under different atmospheric pressures. Cavity subpressure and cavity backwater depth are the main properties examined along with various upstream conditions categorized by water depth and Froude number. Several empirical formulas are proposed and examined with measured data which was mostly obtained by simple optical approach. All results have clear trend with increasing atmospheric pressures, providing insights to engineering applications and future research. Authors should consider the below comments in the revision:
Line 23: add “cavity subpressure index” before P_N
Line 41: Is “fior” a typo?
Line 50: Add a reason for why standard atmospheric pressure is not chosen.
Line 96: Replacing “pressure-reducing” with “airtight” would be more appropriate.
Line 97: Can the aeration step be seen in Figure 1?
Line 105: Definition of P_c?
Line 109: Demonstrate y_0 in Figure 1.
Figure 2(a): Is the L in the vertical label supposed to be L_max?
Figure 6: This figure is missing.
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Unfortunately, the most of my notes are not addressed in the 2nd version of the manuscript at all. I insist on any reasonable reaction on the notes.
The manuscript in the presented form is not ready for acceptance.
Author Response
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Author Response File: Author Response.docx
Reviewer 2 Report
All comments have been well addressed.
Author Response
Thank you for your comments.
Round 3
Reviewer 1 Report
I have to admit that a lot of work has been done, even in the revision process.
However, I do not understand why some notes are still ignored.
All comments from the first round should be addressed properly.
For example, the very simple one in “Notation”, “physical dimensions should be given”. It is a standard in any list of physical quantities to put there physical dimensions. What is the problem?
Figures 1 and 4 should be improved. Fig.1 has inacceptable resolution, definitions of angles and lengths are not clear. In Fig.4 I could see windows in your lab, but not the flow details.
The other points are not perfect, but acceptable.
Author Response
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Author Response File: Author Response.docx
Round 4
Reviewer 1 Report
The manuscript is a bit improved, however some figures are still not acceptable. I recommend do not show Fig.1b. Then, the manuscript is acceptable, however the quality is not very high.
Author Response
Dear Reviewer, Thank you very much for your suggestion. Fig. 1b has been deleted from the manuscript. I will continue to improve the quality of figures in the future writing. Kind regards, WangAuthor Response File: Author Response.docx
Round 5
Reviewer 1 Report
Now the paper is acceptable.
