On the Evolution of Different Types of Green Water Events—Part II: Applicability of a Convolution Approach

Round 1

Reviewer 1 Report

The manuscript concerns the issue of the evolution of different types of green water events. Give some more information about further research, which should be done to find more convolution solutions of the advection-diffusion equation  applied to green water problems.

Author Response

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Reviewer 2 Report

This paper applies shallow water wave theory to estimate the evolution of green water events over a rectangular barge.  The method is tested against extensive model measurements that were previously reported.  The subject is worthy of investigation and the presentation is clear.  The authors state that "the general trends in the experiments are described well" but the overpredictions of the maximum water elevation along the deck are quite large.  That overprediction includes the case where the coefficients of the model were tuned to match the observations.  That makes me wonder about the suitability of the shallow water equations for the problem.  Could there be flow reversal at some depths that spreads the water out?  I would like to see some discussion of this issue and suggestions for how the model might be improved.

It would be interesting to see some comparisons of the model results with the spatial descriptions shown in the bottoms of Figures 4-9.  Room for those comparisons could be made by eliminating a lot of the panels in those figures.  Only a few of them are needed to tell the authors' story and including just a few of them at larger scale would make them easier to read.     

Author Response

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Reviewer 3 Report

This manuscript presents the flume validation of a fast analytic tool to assess the loading of waves overtopping a structure. Such tools are required for structure design to ensure operational safety. This new tool allows the flow of the water across the deck to also be predicted. The validation of the previously published tool gives confidence in the new approach, but clarifies where additional work is required to improve the predictions.

While I am interested in the area of wave overtopping I am not an expert in analytical modelling. My comments focus more on the application of the research and the methods to validate the new tool. The investigation of both single- and multi-events using camera observations is robust. It would be interesting to see the performance of the analytic tool relative to classical tools to demonstrate the improvements of the numerical simulation. There is a 2-step procedure to apply the tool, in which the first step requires parameters to be set using existing data. Can you recommend default parameters to apply where no flume or field data are available so the model could be easily applied by others?

In the abstract it would be beneficial to state who would benefit from use of this analytic tool following the flume validation. This would help attract the right readers.

I am unfamiliar with the term shipping water. Are referring to waves breaking onto a ships deck or are you talking about overtopping and overwash when water goes over a structure or ships side? P2, L47, “The study of water shipping on structures” – I think you are talking about the study of water overtopping a structure.

In the results sections is it possible to classify what “good” or “acceptable” values would be for the chosen error metrics? Including “classic” models for comparison would be of value to demonstrate if the new model provides a notable improvement in prediction or simply a more efficient calculation. From the introduction I was under the impression the new model could simulate multi-valued surface, however, the convolution line in the graphs only present a single-valued surface. Can you clarify what the added capability of the new model is at the start please? Can the new predictions be used to assess the volume of overtopping water? This is critical in addition to the loading forces to design structures in areas at risk of flooding. Can you validate this quantity?

In the discussion, can you comment on the applicability of the analytic model to real world applications? Would there be scale issues?

In the conclusions you state the model performs well, L520. Can you justify how the error is classified as “good”. Can you compare to previous studies and classical models to show the errors are acceptable or typical in this type of study. On their own they look quite large.

The English grammar could be improved throughout. A good proof read after revision is suggested.

 

Some minor suggestions:

Title – would it be clearer to call these events “green water wave events” since the paper is about different breaking waves?

P1, L19. Is it a multi-valued or time-varying water surface? Spray might occur at many elevations at the same time instance but the green (continuous) water surface only has 1 value unless it is a breaking wave. Please clarify in the abstract and avoid technical terms until they are defined. Having L25 before L19 would help as here it is clarified that you are talking about breaking waves.

P1, L20 – delete “in”

P2, L48 – for different

P8, L306 – Capital letter for “The”.

Figure 4 can the x distance be added to one of the lower inserts so the “Experiment x=?” in the caption of the upper inserts can be located in the experiment.

Author Response

Please see the attached file.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

I would like to thank the authors for addressing each comment carefully in the revised manuscript. The addition of the dam-break results clearly illustrates the value of their research.