Laboratory Study on Flow Characteristics during Solitary Waves Interacting with a Suspended Horizontal Plate

Round 1

Reviewer 1 Report

In this manuscript, the 2D kinematic characteristics of the flow are experimentally studied during the interaction of a solitary wave with a plate (deck) fixed in a tank above the level of a fluid at rest. The authors identify the main stages of the interaction process (green water tongue run-up, overtopping, flow separation); provide snapshots of the aerated flow evolution around the deck and measurements of the velocity field at different points in time. They also draw an analogy with the dam-break problem and compare the average flow velocity over the plate with the Ritter solution.

I recommend the publication of this paper if the following comments / suggestions are well addressed.

1.     When we apply a theoretical solution, it is necessary to understand what mathematical model this solution corresponds to. Please indicate which equation satisfies the function h given by formula (1).

2.        It would be nice to improve the quality of Figs. 3 and 4.

3.     There is a typo in the first formula (2), since the dimensions in the left and right parts do not match. I guess it should be (gh_x)^1/2 instead of (g/h_x)^1/2. Here it would also be good to indicate for which model this solution was obtained. This is probably a classic 1D non-linear model of shallow water flows (Saint-Venant equations).

4.      The solution for the dam-break flow is determined for t>0 in the region  -(gh₀)^1/2<x/t<2(gh₀)^1/2. This solution continuously connects the state of rest h_x=h₀, U_x=0 for x/t<-(gh₀)^1/2 and the dry bed for x/t>2(gh₀)^1/2. Therefore, there are no singularities in this solution.

 

5.   Section 3.2 requires revision and corrections, taking into account the comments made.

Comments for author File: Comments.pdf

Author Response

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Reviewer 2 Report

Manuscripts presents the results of a laboratory experiment conducted to understand the green water effect on a fixed deck caused by a solitary wave. It is certainly an interesting subject, yet, unfortunately at present the manuscript have some significant shortcomings and cannot be recommended for publication.  

1) First and foremost, the wave scaling they established is problematic and is not plausible when converted into geophysical scale. A solitary wave (that presumably represent a tsunami) with H/h = 1/3 can only occur near the coast and be induced only by an extremely large tsunami. In the case of offshore platforms or ships in deep water where the water depths are in the order of hundreds of meters the solitary wave height according to their scaling will be > 30 meters. Yet, we know that in open ocean tsunami heights are much lower and energy is distributed across the long wavelength (order of hundreds of km). Therefore, their experiment results are hardly applicable to real life and are not very useful.  

2) I also do not understand why they had just used single wave for the entire experiment. They could have easily run tests with different wave heights, which could have provided a suite of data for various cases. Similarly, instead of having a fixed deck height, they could have changed the clearance underneath the deck.  

3) Although both tsunami and storm surge are long wave phenomena, they cannot be represented by the same wave as their length scales are completely different. The wave that authors generated in the wave is suitable for a large tsunami, therefore they need to remove all mentions of the storm surge from the text.

Author Response

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Reviewer 3 Report

I commend the authors for tackling the green water problem experimentally using a solitary wave model. I suggest the following:

1) Include the Goring reference, since [36] doesn't mention its name. 

2) The celerity formula is an important part of the soliton's kinematics, it should be shown separately as a numbered equation and derivation of explanation for its final form included.

3) Figure 1c) labelling of y-axis is very difficult to read. Use symbols (form Eq. 1) instead of spelling out wave elevation, for example. 

4) Not sure if an uncertainty analysis has been carried out as the experimental results do not exhibit any error bars with confidence interval in Fig. 6 or Fig. 7. This should be indicated in the paper.

5) It is not clear in the conclusion that the disagreement with the Ritter's solution for t< 0.35 s (Fig. 7a-d) is clearly explained.

Author Response

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Round 2

Reviewer 2 Report

I thank authors for going great lengths in improving their manuscript. This version is significantly better than the original by all means.

I do not have any other major comments rather I would like to point out that Figures 3 and 4 are very hard to follow. It would be great if they replace one of them with a colored surface plot of the flow speed, where reader can grasp the variations in it clearly. Still they can overlay sparse flow vectors on top as they are currently all mingled together and do not provide any useful insight.

Author Response

Thanks for your comments. The multicolored contour maps representing the magnitude of the flow velocity have been embedded in the Figure. 3 and Figure. 4. Besides, the velocity vectors have been retained in the figures. There is a clear indication of the velocity distribution in the revised manuscript, especially for the areas where the vortices are obvious. After modification, we hope that the reader is able to perceive the variety of the global velocity more intuitively.