A Near-Shore Linear Wave Model with the Mixed Finite Volume and Finite Difference Unstructured Mesh Method
Round 1
Reviewer 1 Report
The manuscript proposed a Near-Shore Wave Model with the Mixed Finite-Volume and Finite-Difference Unstructured Mesh Method. This proposed model is verified and apply for some cases. The advantage of the new model is that the propagation of waves from deep water to shallow water in nearshore and interaction between waves and river inflows may be carried out seamlessly. The manuscript is interesting and it is suitable for publication in the journal.
Author Response
Thanks the reviewer for your positive comments. I have modified the manuscript and hope to receive your continued support and advice.
Reviewer 2 Report
In my opinion this manuscript should not be accepted for publication in the present form because of the following issues.
- The introduction is too general and it does not cover the state-of-the-art in terms of the novelty aspects of the present work, i.e. numerical method issues.
- The method section is also too long given that no new model is presented.
- The novelty aspects of the work in terms of the numerical methods should be shown using harder validation problems like the ones in the following articles for breaking and non-breaking waves:
- Chawla, J.T. Kirby, Wave transformation over a submerged shoal, CACR Rep. No. 96-03, Deptartment of Civil Engineering, University of Delaware, 1996.
- Chawla, A., and Kirby, J. T., Monochromatic and random wave breaking at blocking points, J. Geophys. Res., 107( C7), doi:10.1029/2001JC001042, 2002.
Author Response
Thanks for your review comments. We have revised the manuscript to address some concerns. Below is a list of specific replies to the review comments:
(1) "In my opinion this manuscript should not be accepted for publication in the present form because of the following issues."
Reply: We would like to stress the new contributions of the present study below as stated in the Abstract:
“New contributions of the present study lie primarily in the numerical method adopted; they include: (a) a new operator-splitting method that allows an implicit solution of the wave action equation in the geographical space; (b) mixed finite-volume and finite difference method; (c) unstructured polygonal mesh in the geographical space; and (d) a single mesh for both the wave and current models that paves the way for the use of the one-model approach.”
Indeed, the contribution is a new numerical model, not new physical process models. We have added new references in our literature study section to show that unstructured mesh is the new trend in recent wave model development. In particular, the development of the polygon-based wave model is new and has not been reported to our knowledge.
(2) "The introduction is too general and it does not cover the state-of-the-art in terms of the novelty aspects of the present work, i.e. numerical method issues."
Reply: We have added a number of new recent-year references (see the list below) along with discussion to show the following: (a) The physical processes adopted in the third-generation wave models are still the current state-of-the-art and have been used in recent-year applications. (b) The unstructured mesh for the wave model has been the recent trend in numerical model development. However, all have used triangular cells; our proposed flexible mesh (polygon-based) is unique and has not been reported to our knowledge.
List of new references added:
Anton, I.A., Rusu, L., Anton, C. (2019). Nearshore Wave Dynamics at Mangalia Beach Simulated by Spectral Models. J. Mar. Sci. Eng., 7, 206; doi:10.3390/jmse7070206.
Cavaleri, L., F. Barbariol, A. Benetazzo, and T. Waseda. (2019). Ocean Wave Physics and Modeling: The Message from the 2019 WISE Meeting. Bulletin of the American Meteorological Society, 100, ES297–ES300.
Farhadzadeh, A., and Gangai, J. (2017). Numerical modeling of coastal storms for ice-free and ice-covered Lake Erie. Journal of Coastal Research, 33(6), 1383-1396.
Kim, K.O., Yun, J.-H., and Choi, B.H. (2016). Simulation of Typhoon Bolaven using integrally coupled tide-surge-wave models based on locally enhanced fine-mesh unstructured grid system. Journal of Coastal Research, Special Issue 75 (1127-1131).
Qu, K., Tang, H.S., and Agrawal, A. (2019). Integration of fully 3D fluid dynamics and geophysical fluid dynamics models for multiphysics coastal ocean flows: Simulation of local complex free-surface phenomena. Ocean Modeling, 135, 14-30.
Rusu, E. (2016). Reliability and Applications of the Numerical Wave Predictions in the Black Sea. Front. Mar.Sci.3:95. doi: 10.3389/fmars.2016.00095
(3) "The method section is also too long given that no new model is presented."
Reply: We have re-examined the “Governing Equation” section and attempted to shorten the section. In its present form, only the essential governing equations and the relevant physical processes (i.e., wave breaking, diffraction and bed friction) have been presented; other process terms have been referred to our project report (Lai and Kim 2020). Since the primary contribution of the paper is the development of a new numerical method, we feel the relevant governing equations should be presented so readers may repeat what we did. If anything can be cut, the section on the “Initial and Boundary Conditions” is a potential candidate. As of now, we decide to keep the current presentation. However, we are open to ideas on how to shorten the section if the reviewer or the Editor may provide specific suggestions to us.
(4) "The novelty aspects of the work in terms of the numerical methods should be shown using harder validation problems like the ones in the following articles for breaking and non-breaking waves:
Chawla, J.T. Kirby, Wave transformation over a submerged shoal, CACR Rep. No. 96-03, Deptartment of Civil Engineering, University of Delaware, 1996.
Chawla, A., and Kirby, J. T., Monochromatic and random wave breaking at blocking points, J. Geophys. Res., 107( C7), doi:10.1029/2001JC001042, 2002."
Reply: We thank the reviewer for providing us with the two references which contained more prospective cases for model verification. We will look forward to simulating the cases in the next phase of our ongoing project. We do not include these additional efforts in the current paper for the following reasons: (a) The primary contribution is the development and verification of a new numerical method, not new physical processes. There are already plenty of cases presented in the current paper that verifies that the correct equations are solved and the equations are solved correctly by the new model. The simulated cases have covered various wave processes such as the shoaling, refraction, wave breaking and wave diffraction. More cases are probably warranted if new physical process models are proposed (which is not the case); then more validation cases are needed. (b) Time does not allow us to carry out these cases for a timely publication of the present paper.
We hope our revision and replies are satisfactory to the reviewer and the Editor.
Round 2
Reviewer 2 Report
In my opinion the manuscript should be published in its present form only after the title is changed into "A Near-Shore Linear Wave Model with the Mixed Finite-Volume and Finite-Difference Unstructured Mesh Method" since practically all cases examined correspond to linear waves.
