Numerical Investigation of Critical Hydraulic Parameters Using FLOW-3D: A Case Study of Taunsa Barrage, Pakistan

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The content of the paper is interesting and useful for practical purposes. There are a few concerns, though:

1. The present study with the 3D CFD model (FLOW3D) is compared with another numerical study, using HEC-RAS. It would be good to see comparisons with experimental measurements, either in the laboratory, or from field observations.

2. Figure 13 shows "Longitudinal Velocity". Is it the depth averaged x-direction velocity at the section? It is not clear, since it is not explicitly explained anywhere. If that is the case, the net forward velocity cannot be negative, as shown in the figure.

3. Research Motives and Problem Statement are discussed on Section 1.4. However, after going through the complete paper (till the end of the Conclusions section), it remained unclear as to how the results presented in the paper are likely to address the hydraulic problems of the Taunsa Barrage. In fact, the results presented (broadly, these are the flow patterns in the stilling basin under 4 different tail water levels) are rather very generic: these would probably be true for any barrage - not just Taunsa Barrage.

Comments on the Quality of English Language

I am not a native English speaker, hence may not be an authentic commentator on this issue. However, I find the English quite good, except that there are a few grammatical mistakes here and there.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is written clearly, but the scientific novelty is not so high. Introduction section looks too long, and it repeats the introduction sections in other papers published by the same authors recently. The paper is of practical interest and I recommend it for publication.

Author Response

"Please see the attachment." 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

p1. " It is a chaotic phenomenon in which the flow changes suddenly from supercritical to subcritical conditions" or reversely ! define supercritical / subcritical conditions ; "A hydraulic jump (HJ hereafter) occurs in gravity-driven flows when Froude Number (Fr) falls below unity" in fact "crosses" unity -- recall froude number ; "the rollers’ deflection from the vegetated layer" please precise what deflection (from...) means quantitatively, or illustrate ;

Lines 40-84 are messy : please shorten and highlight the message in a nutshell

Section 1.2: is the message " The results indicated that the available tailwater levels were appropriate for the formation of HJ." ? Then precise the meaning of "available" tailwater levels (Figure 8 helps)

Ref 35 is unclear

Summarize the message of lines 118-160: to which extent is CFD capable of forecasting HJs ? (a table could help)

Figure 3 is too ugly to be read -- same for axes in Fig 5

Line 277 "conservation" not "conversation"

 

Finally, I find that the article lacks one clear innovation.

I understand that the authors initially surveyed the litterature to investigate how to vary (numerical) model parameters and get an idea of HJ characteristics. A first conclusion is thus: vary "velocity profile, Froude number, free surface profile, shape of stilling basin, tailwater, and turbulent kinetic energy".

Then, one innovation could be to propose a clear strategy based on varying the latter CHP and get an idea of HJs.

But I hardly see such a clear methodology (it may be drowned in the text) -- and I do not see any discussion of the numerics reliability in any case, which is very regrettable.

 

Author Response

"Please see the attachment." 

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The message is still a bit unclear, but the article has improved

Author Response

We are highly grateful to the reviewer#3 for providing valuable comments in the first review report which helped us to improve the manuscript. The authors addressed the comments and amended the manuscript in line of those comments.

For the present general comment, the authors would like to clarify the goals of this study which will hopefully deliver the clear message as per comment of the reviewer 3. 

Please find the attached response.

Author Response File: Author Response.pdf