Advances in Numerical Reynolds-Averaged Navier–Stokes Modelling of Wave-Structure-Seabed Interactions and Scour
Round 1
Reviewer 1 Report
The present paper represents an interesting review tackling important coastal aspects, especially related to the erosion induced by artificial structures and their modeling through the most common numerical approaches. In general, the paper is well written and organized, but improvements are needed to make it suitable for publication.
The introduction addresses many important aspects of the numerical modeling of the overall dynamics generating around coastal and offshore structures. However, an important modeling type is only briefly introduced, i.e. the two-dimensional horizontally (depth-averaged) modeling. Although its degree of approximation, it has been demonstrated that such models can be important for a good representation of the nearshore dynamics. The authors are suggested to briefly summarize the models that simply couple the depth-averaged shallow water equations with the Exner equation (e.g., Briganti et al., 2012, 2016; Postacchini et al., 2012), describe the discretization of infiltration-exfiltration processes (e.g., Perera et al., 2019; Pintado‐Patiño et al., 2015), deal with scour and deposition due to the presence of structures (e.g., Postacchini et al., 2016; Son et al., 2020). Such models are important also in view of the reduced computational cost (see lines 52-53).
The processes described in section 2.2 are fine, but I would include/add more recent publications (e.g., see points B, C), due to the review nature of this work. Further, I would add the important process of wave spectrum transformation and frequency dispersion occurring over submerged breakwaters, as depicted by Battjes & Beji (1991).
Section 3 should be integrated (inside or in addition to section 3.1) with the approach based on depth-averaged equations, i.e. models based on either Boussinesq-type equations or nonlinear shallow water equations (e.g., Briganti et al., 2016; Son et al., 2020).
I would improve section 4 by including some examples of applications, also with sketches or pictures showing recent results, rather than tables. Further, the way this section looks like is not straightforward, with many descriptive parts, some of them being redundant if compared to section 3. Again, think about moving or integrating such descriptive concepts into section 3.
Specific comments
- At line 254, what is “dn50” (perhaps “d50”)?
- Please, better introduce terms E and D (line 268).
- Is the acronym “NS” introduced somewhere (see line 272)?
- At line 361, it should be “due to”.
References
Battjes J.A., & Beji S. (1991) Spectral evolution in waves traveling over a shoal. In: Proceedings of the Nonlinear Water Waves Workshop, Bristol, pp 11–19.
Briganti, R., Dodd, N., Kelly, D., & Pokrajac, D. (2012). An efficient and flexible solver for the simulation of the morphodynamics of fast evolving flows on coarse sediment beaches. International Journal for Numerical Methods in Fluids, 69(4), 859-877.
Briganti, R., Torres-Freyermuth, A., Baldock, T. E., Brocchini, M., Dodd, N., Hsu, T. J., ... & Postacchini, M. (2016). Advances in numerical modelling of swash zone dynamics. Coastal Engineering, 115, 26-41.
Perera, E., Zhu, F., Dodd, N., Briganti, R., Blenkinsopp, C., & Turner, I. L. (2019). Surface-groundwater flow numerical model for barrier beach with exfiltration incorporated bottom boundary layer model. Coastal Engineering, 146, 47-64.
Pintado‐Patiño, J. C., Torres‐Freyermuth, A., Puleo, J. A., & Pokrajac, D. (2015). On the role of infiltration and exfiltration in swash zone boundary layer dynamics. Journal of Geophysical Research: Oceans, 120(9), 6329-6350.
Postacchini, M., Brocchini, M., Mancinelli, A., & Landon, M. (2012). A multi-purpose, intra-wave, shallow water hydro-morphodynamic solver. Advances in Water Resources, 38, 13-26.
Postacchini, M., Russo, A., Carniel, S., & Brocchini, M. (2016). Assessing the hydro-morphodynamic response of a beach protected by detached, impermeable, submerged breakwaters: a numerical approach. Journal of Coastal Research, 32(3), 590-602.
Son, S., Lynett, P., & Ayca, A. (2020). Modelling scour and deposition in harbours due to complex tsunami‐induced currents. Earth Surface Processes and Landforms, 45(4), 978-998.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The authors present a review of numerical modelling of sediment transport around marine structures, focusing on interactions (wave-structure-seabed) and resulting morphological changes (scours). As a review, the paper is dense, but the choice of the paper's organisation allows an easy and comprehensive reading.
The main concern I would like to address, is the paper focus mainly (even in totality) on Navier-Stockes based numerical models. I agree NS is the most implemented approach but therefor not the sole in the area of marine sediment transport around structures. As an example, I would like to mention just one, based on Boltzmann equation, implemented as Lattice Boltzmann Method (LBM). A huge amount of work is now available on this approach and proofs is now made of it's non exotic aspect.
My concern is not to ask the authors to add and treat the LBM aspects in their paper, but more to propose to change the title of the paper:
"Advances in numerical Navier-Stokes modelling of wave-structure-seabed interaction and scour"
so that the reader will better know the context of the review.
Minor remarks along the paper
line 230: authors give values in parenthesis, as Φ is in general used for porosity notation, I would replace by "Φ ∈ {0.35-0.65}"
line 233: replace "Eqs. 4, 6 and 6..." by "Eqs. 4, 5 and 6..."
line 238: replace "R.H.S." by "right hand side"
line 238: replace "Eq 6" by "Eq 5"
line 243: "...the governing equations in the wave-structure module are the RANS equation.", I propose to replace by "...the governing equations in the wave-struture module in the case of RANS equations."
Between line 260 and 261 (not numbered): "From the suspended concentration...", I propose to replace by "Concerning the suspended concentration,..."
Line 391: "..,being Ws,..." should be "...Ws being,..."
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The manuscript has been significantly improved and looks good. I believe it merits to be published after a light revision.
- Battjes and Beji’s reference is not correct, e.g. see the original workshop proceedings or the link to their work: https://repository.tudelft.nl/islandora/object/uuid%3Af837312b-1acc-4fa7-8f37-4b0ef821edde
- At lines 168 and 202, section reference should be added.
- At line 266, do the authors mean “volumetric reference concentration at the bed, cs” ?
- At line 320, please amend with “Navier-Stokes”.
Author Response
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Author Response File: Author Response.pdf
