Effect of a Submerged Vane-Field on the Flow Pattern of a Movable Bed Channel with a 90° Lateral Diversion
Round 1
Reviewer 1 Report
Title: Effect of a submerged vane-field on the flow pattern of a movable bed channel with a 90° lateral diversion
Author: J. Baltazar, E. Alves, G. Bombar, A. Cardoso
Journal: Water MDPI
General comment
The paper describes an experiment carried out in the presence of a movable bed with a main channel and a lateral diversion. The effects of a vane field on both morphology and flow field are investigated by means of echosounders and ultrasonic sensors, as well as with acoustic velocimeters.
Results discuss the comparison between the no vane case (NV experiment) and a vane field case (VF experiment), in terms of bed morphology, velocities and turbulent kinetic energy.
Though the paper deals with an interesting topic, the experimental method seems to me to be debatable especially as regards to the identification of equilibrium conditions, to the amount of sand which is introduced during the tests, to the no slip boundary condition at the walls. More specifically:
- In the experimental setup and procedure section it is reported that every 1.5 h a fixed amount of sand is poured in the channel; the experiment was stopped when the sand inflow and outflow are equal. According to this, during the experiment the sand quantity is changing, while the experiment should start as soon as the sand continuity (inflow equal to outflow) is reached. Otherwise, results could be not representative of stable and equilibrated conditions. Moreover, since only one experiment was carried out, without repeating it under the same experimental conditions, there is no proof that the same situation in terms of bed morphology and hydrodynamics can be reproduced. A more detailed dataset, including the repetition of some tests should be performed.
- In some figures (e.g. 6, 9, 10..) something strange is observed. The arrows close to the wall should decrease to zero in order to respect the wall no slip condition, however in some cases they increase just close to the boundary and nothing is said or commented about that. Moreover it seems that no correspondence between colorbar and arrows is occurring.
Specific comments
Line 3: water discharge ratio is mentioned but not defined here.
Line 36 and following: a sketch would help.
Figure 1: provide an ensemble sketch reporting the whole system including the reservoirs, belt, pumps, etc.
Line 153: 23.9 kg: is this amount trapped by sand traps?
Line 226:considerations on the effectiveness of the vane field could be recovered from morphology tests but are missing here.
Line 231: at which elevation from the bed? How many vertical positions? Always the same for each station?
Figure 5: the zones could be framed in order to provide an indication of (x, y) min and max.
Figure 6: colorbar and arrows seem not to agree one with the others.
Line 322: this observation is however not supported by experimental evidences that show that the scour and deposit are roughly similar for NV and VF tests.
Line 474: typo in Figure 16a,b,c
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The Authors present an interesting topic in the manuscript, which presents the effect of a submerged vane-field on the flow pattern and bed morphology near and inside the entrance reach of a movable bed 90º lateral diversion.
However, in my opinion, before the paper can be considered for acceptance, it requires revision in several points. I highlighted general comments below and some detailed ones are in the attached PDF file.
1) The English of the manuscript needs to be polished and corrected by a native speaker. In several instances the English is too colloquial and not formal enough as it is required for scientific publications.
2) Many statements lack proper references, which need to be presented, e.g. 1st paragraph of the Introduction section (not even one reference for general statements!).
3) The Introduction section requires many changes and clarifications for more clear and specific presence.
4) In the results, authors shoul present results and then, refer to correcponding figures, not present what is on the figure.
5) For such topic, the number of references is very low. This is also due to lack of appropriate refferences to many statements and sentences with general explanations.
6) Figures need some work to increase their visibility (quality and mostly font enlargement).
7) Conclusions section should be rewritten in more clear and consistent way. It should be also shortened.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
This study investigated the effect of vane on flow pattern, which is very interesting topic. However, there are too many figures, and the results are too complex. and it is necessary to focus on the core content and add more in-depth discussion. Thus, it is hard to accept with present state.Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
This manuscript is about experimental analysis of the confluence channel with the live bed condition.
- Experimental setup with photos will be helpful for the readers.
- Methods for the time averaging velocity should be introduced with consideration about the randomness.
- inspiration with quantitative parameters from the flow fields is necessary.
- notation of the approximately can be changed into "~"
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper describes an experiment carried out in the presence of a movable bed with a main channel and a lateral diversion. The effects of a vane field on both morphology and flow field are investigated by means of echosounders and ultrasonic sensors, as well as with acoustic velocimeters. Results discuss the comparison between the no vane case (NV experiment) and a vane field case (VF experiment), in terms of bed morphology, velocities and turbulent kinetic energy. The paper is improved in readability with respect to the previous version but however a debatable observation cannot be overcome. Indeed the authors claim that “on the basis of decades of work on morphodynamics (scouring at piers and abutments; movable bed confluences, etc.), that we will always approach the same average bed and flow structures” and do not agree on the need to repeat the tests. However, decades of work are definitely not enough to prove that the same conditions would be reached without any test repletion, thus I invite the authors to effectively check to what extent there is total overlap on two test repeated with the same conditions.
Reviewer 2 Report
Athors improved their paper since the first submission and corrected almost all mistakes found during the previous round of review. For some of them, they presented sufficient explanations for not doing the changes. I do not have additional suggestions. Thus, the paper can be published in Water journal in the current form.
Reviewer 3 Report
There are no special comments.
Please check again thoroughly for typos and errors
