In the author reply, many of the details I requested are given, but a lot of them are not included in the revised manuscript, thus leaving a potential reader with the same questions. The coupling between the two models and the setup of the IH2VOF should be dealt with in more detail in the revised manuscript.
I still see some challenges in the coupling the two models. This, however, can be overcome by stating some of the possible limitations. Please see the detailed comments below.
1) I asked for typical grid sizes in the RANS model. This is given in the reply and I feel this information should be present in the paper.
a. Further the authors state that the model do not allow more than 5499 cells in X. Why is that? Is that a choice of the authors?
b. It is stated that the aspect ratio between x and z was 5. I completely understand the need for such a large aspect ratio, to limit computational time. However, large aspect ratio has, as shown by Jacobsen et al (2012), an impact on the position of the breaking point. Despite this, I still think that IH2VOF handle more accurately the physics of the tsunamis in this region than COMCOT, and thus it is justified. A comment should however be made that such large aspect ratios, might lead to slightly premature breaking.
c. An equation is given for determining delta z. Where does this come from? The effect of it can clearly be seen, and to me it seem a reasonable way of automizing the process. Again, I feel that this information should be present in the revised manuscript.
2) I asked for boundary conditions for IH2VOF model, and the authors replied that a log wall distribution was used. This seem reasonable, but, if the mesh is not graded near the bed, the y+ values must be extremely large potentially putting the value of the first grid point outside the log layer. Please discuss the possible impact of this. Further, please also provide the wall functions for k and epsilon. Finally, another reference than Lara et al. (2006) should probably be used here, as the turbulence model is not described in this paper.
3) I asked how the x_cut positions was determined. The authors has given a clear and satisfying answer, but not included this explanation in the revised manuscript. Please do so. Further in the response the authors called the model a LSWE model. I thought it was a NLSW model. If it is a NLSW do not alter anything, but if it is a LSWE model, please justify why this sufficient for the simulations since tsunami close to the shore can definitely be nonlinear.
4) I asked about the position of x_cut in relation to capturing the physics of the tsunami. A figure is added in the reply, but this figure the lines cannot clearly be distinguished and thus is hard to read. Further, I do not feel that this figure answers the question posed. One of the physical features a NLSW model cannot handle, but a VOF model can, is the undular bores. These might show further offshore than x_cut. I understand the practical limitation, but feel that a comment stating that there might be situations where the NLSW model is not properly handling the physics, before the VOF models takes over, is warranted.
5) I asked about reflection between the two models. I appreciate what the authors are trying to do, and can see that using the unaltered wave will limit reflection between the models. However, I think that this approach will give difficulties in certain cases. It the beach is steep, the tsunami wave will be reflected entirely, as the steep beach acts more or less likke a vertical wall. In this case a standing wave will be present similar to that shown in Madsen and Fuhrman (2009) figure 9a. By using the unaltered waveform this behavior cannot be captured. This should be reflected upon in the revised manuscript.
6) I asked for more details regarding the calculations for figure 4. These have been provided, but some things are still unclear. Now it is stated that L_i=50/tan(beta_0). How can this be true? In page 10 lines 17-19 it is stated that horizontal length of the domain comes from a separate simulation using COMCOT only.
7) I asked for a validation of the Hybrid model. I fully appreciate that both models have been used with great success in the past, and I did not question the validity of the models. In Lara et al. (2006) however smaller aspect ratios were used compared to here. The additional figure indeed provides validation for that IH2VOF can handle run-up. It is however important that the mesh for these simulations were performed using the same rules as in the present paper. I.e. delta z= (K H)/10 *0.05) *0.05, and r=5/1. Is this the case? If not, I would argue that the validation is made on a much finer mesh than the simulations in present paper. In this case, I do not feel that the model is validated satisfactory, and new validation simulations should be made.
The accompanying text to the figure is also unclear. In page 13 line 4 it is stated that the validation and coupling of the numerical models was made by comparing to experimental results. In the legend in the figure however, it is only the IH2VOF model, and thus no coupling between the models are present. Which of these are correct?
8) The authors have compared now both to Synolakis as well as Madsen and Schaëffer. I am however curious how the results from Synolakis as well as Madsen and Schäeffer were obtained, as these were created for only a single sloped region. Was an average slope calculated? Or only beta_1 or beta_0 used? Please describe how it was done, and why this is the best approach.
9) I asked about the determining of period and wave height. In the reply the authors state that no serious differences between trough led or crest led were experienced. What about difference between a single wave, and a leading depression n-wave for instance. With the N-wave height is the summation of the positive negative amplitude, whereas the wave height of the single wave is just the positive amplitude. I can see how a single wave with a similar positive amplitude as a leading depression N-wave, will run-up similar but I would imagine a single and an N-wave with the same wave height will run-up differently. Perhaps it would be better to called maximum positive amplitude in the revised manuscript rather than wave height.
Jacobsen, N. G., Fuhrman, D. R. & Fredsøe, J. 2012 A wave generation toolbox for the open-source CFD library: OpenFoam (R). Int. J. Numer. Meth. Fluids 70, 1073–1088.
Madsen, P. A., Fuhrman, D. R., 2008. Run-up of tsunamis and long waves in terms of surf-similarity. Coast. Eng. 55, 209-223.