On the Uncertainty of the Image Velocimetry Method Parameters

Round 1

Reviewer 1 Report

Dear authors,

please find comments in the attached manuscript. Two main points that need to be addressed are:

1. Comprehensive rewriting in terms of English syntax and grammar. Please share and review your manuscript with a native speaker or other adequate person. 

2. There is a lack of describing some basic methodology components on which you built on with details and the reader cannot follow. Please set the basics, provide architecture/methodology figures and make comparisons.

More details in the attached file,

Best regards

Comments for author File: Comments.pdf

Author Response

Please see attached pdf file.

Author Response File: Author Response.pdf

Reviewer 2 Report

General comment: This paper focus on the application sthocastic simulations for studying the impact of setting parameters on the accuracy of LSPIV surface flow estimations. For this purpose authors used a case study published by Pears et al. 2019. The topic is interesting and actual because there is need to estimate the uncertainty associated to the image velocimetry estimations due to environmental factors and parameter setting of the involved techniques. However, at the moment, the presentation of the topic needs more details expecially to clarify the advances achieved respect to the previous works present in literature. I believe that the manuscript could be published pending some major revisions.

Specific comments:

• Abstract and introductory section seems definitely too generic, and does not focus on the core of the topic that is the rule of setting parameters on PIV accuracy. Moreover I think that some previous works have been neglected and it could be considered in presenting the main topic of the article in a more complete way, expecially respect to the impact of interrogation area size on the surface velocity estimations. For this purpose, several other references dealing with the topic are suggested in the final part of this review and could be used to give a more complete framework of the topic and to enphatize the novelty of this work.
• Line 89 – These parameters are required inputs or simply suggested? For example, in PIVlab the CLAHE algorithm is at most suggested to improve the visibility of features. Please clarify this point.
• Line 91 – Other authors demonstrate in their works that seeding density is one of the most relevant parameters in the determination of the interrogation areas and velocity field (see references).
• Line 98 (Section 2). It is not clear what is the frame rate and the length of frame window that authors used for their analysis. Please clarify this point.
• Line 137 – Authors use contrast adjustment on the frames. It would be useful to show an example of original frame and pre-processed one.
• Line 145 – I suggest to present the case study in a more complete way including some figures/tables that summarize all the experimental information (camera, frame rate, number of frames etc).
• Line 146 – Are these data avainable? Please provide some information about this.
• Line 168 – Please clarify the term density in the whole document.
• Line 185 – Why authors not consider the configuration with L values equal to 96 and 128 that are used for the analysis of IA size for the Montecarlo simulations?
• Line 220 (Figure 6, 7 and Table 3) – How it is it possible to do this comparison? Pears at al. in their work didn’t apply any pre-processing algorithm on their frames and use other parameter settings (cross-correlation algorithm, interrogation area).
• Line 284. Please correct with Dal Sasso et al [28].

References

Adrian, R. J. (1991). Particle-imaging techniques for experimental fluid-mechanics. Annual Review of Fluid Mechanics, 23, 261–304. https://doi.org/10.1146/annurev.fl.23.010191.001401

Adrian, R. J. (2005). Twenty years of particle image velocimetry. Experiments in Fluids, 39(2), 159– 169. https://doi.org/10.1007/s00348-005-0991-7

Kähler, C. J., Scharnowski S., Cierpka C. (2012a). On the Uncertainty of Digital PIV and PTV near Walls. Experiments in Fluids. doi:10.1007/s00348-012-1307-3.

Kähler, C. J., Scharnowski S., Cierpka C. (2012b). On the Resolution Limit of Digital Particle Image Velocimetry. Experiments in Fluids 52(6): 1629–39.

Keane, R.D., Adrian, R.J. (1992). Theory of cross-correlation analysis of PIV images. Applied Scientific Research 49, 191–215. https://doi.org/10.1007/BF00384623

Keane, R. D. and Adrian, R. J. (1990). Optimization of particle image velocimeters. Part I: Double-pulsed systems. Measurement Science and Technology 1, 1202–1215.

Keane, R. D. and Adrian, R. J., Optimization of particle image velocimeters (1991). Part II: Multiple-pulsed systems. Measurement Science and Technology, 2, 963–974.

Perks, M. T., S. Fortunato Dal Sasso, A. Hauet, S. Pearce, S. Peña-Haro, F. Tauro, S. Grimaldi, B. Hortobágyi, M. Jodeau, J. Le Coz, I. Maddock, L. Pénard, and S. Manfreda,Towards harmonisation of image velocimetry techniques for river surface velocity observations, Earth System Science Data, 12, 1545–1559,  (doi: 10.5194/essd-12-1545-2020) 2020.

Author Response

Please see attached pdf file.

Author Response File: Author Response.pdf

Reviewer 3 Report

In hydraulic testing, more and more precise techniques for determining velocity fields are being sought. I consider the paper as a interesting research material and the possibility of further development of the PIV technique.
I recommend publication of this paper after minor revision.
The topic of the manuscript you propose clearly fits the journal scope from my perspective.
My basic remarks to the paper:
1. The abstract needs a careful revision to clearly focus on the “why”, “how” and present the “key results”.
2. In Introduction: What is the main aim, significance and applicability of the research results? What is the further application of this research? The review of the previous researches related to the case study should be created (very shortly at the end of the Introduction section), but also accentuate the importance and application of the results which are obtained in this research for further research and practice!
3. The subject is current and very important. Unfortunately, there is also a lack of more detailed information on how to translate information about the distribution of surface velocities into total flow values.
4. In the Discussion, there is no reference to the results of other researchers. The whole discussion was basically reduced to analyzing the results. This is a serious problem in this work.
5. The literature review has been limited to only 28 articles and books. It's a bit too little. Especially that the Discussion lacks references to the results obtained to the work of other researchers. This is very important for a good scientific work! It should be demonstrated that in the scope of this Editorial Office there are also similar topics to those presented in paper.

Overall, I think that the proposed manuscript has a good basis, but would need some additional work to increase its significance, originality and rigor. I hope that the comments above will help you to improve your manuscript.

Author Response

Please see attached pdf file.

Author Response File: Author Response.pdf