Influence of Morphological Parameters on the Flow Development within Human Airways
, Carlos Alberto Duque-Daza †and Diego Alexander Garzón-Alvarado †Round 1
Reviewer 1 Report
The authors presented a numerical study on the Influence of morphological parameters on the flow development within human airways.
Some quantitative results are to be added to the abstract.
The novelty of the work is to be clearly stated.
Have you solved a 3D or 2D configuration?
The boundary and initial conditions are to be expressed mathematically.
Have you considered a periodic inlet velocity?
Is the velocity constant at all the branches ?
The numerical method is to be detailed.
A figure presenting the used mesh is to be added.
A grid sensitivity test is to be performed.
A verification of the numerical model is to be performed, by comparing with earlier published results.
Why the fluid-structure interaction is not considered?; have you considered all the boundaries as rigid ?
Some 3D flow structures are to be presented.
The authors solved time-dependent governing equations, thus temporal variations are to be presented.
What are the properties of the air ? and is it considered a humid air?
A nomenclature is to be added.
The discussion is to be improved by physical interpretations.
The paper is to be checked against misprints and grammatical mistakes.
Author Response
Dear Reviewer,
Please see the attachment.
Best Regards
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Review of a manuscript titled “Influence of morphological parameters on the flow development within human airways”
The authors have studied the human airways characteristics like bifurcation angle and carina rounding radius. They have studied two different Re, 500 and 2000 and analyzed them in terms of velocity profiles, wall shear stress, and secondary flow. Even though the analysis is acceptable, many details of the numerical model are missing. I think the authors have to take the comments below seriously to get the manuscript acceptable level.
1. The literature review done by the authors is not comprehensive.
Faizal, W. M., Ghazali, N. N. N., Khor, C. Y., Badruddin, I. A., Zainon, M. Z., Yazid, A. A., ... & Razi, R. M. (2020). Computational fluid dynamics modelling of human upper airway: A review. Computer methods and programs in biomedicine, 196, 105627.
Zobaer, T., & Sutradhar, A. (2021). Modeling the effect of tumor compression on airflow dynamics in trachea using contact simulation and CFD analysis. Computers in Biology and Medicine, 135, 104574.
Hassani, K., & Khorramymehr, S. (2019). In silico investigation of sneezing in a full real human upper airway using computational fluid dynamics method. Computer methods and programs in biomedicine, 177, 203-209.
Mason, E. C., Wu, Z., McGhee, S., Markley, J., Koenigs, M., Onwuka, A., ... & Zhao, K. (2021). Computational Fluid Dynamic Modeling Reveals Nonlinear Airway Stress during Trachea Development. The Journal of Pediatrics, 238, 324-328.
Xu, X., Wu, J., Weng, W., & Fu, M. (2020). Investigation of inhalation and exhalation flow pattern in a realistic human upper airway model by PIV experiments and CFD simulations. Biomechanics and modeling in mechanobiology, 19(5), 1679-1695.
Piemjaiswang, R., Shiratori, S., Chaiwatanarat, T., Piumsomboon, P., & Chalermsinsuwan, B. (2019). Computational fluid dynamics simulation of full breathing cycle for aerosol deposition in trachea: Effect of breathing frequency. Journal of the Taiwan Institute of Chemical Engineers, 97, 66-79.
2. What is the mean velocity variation considered during the inhalation and exhalation process in the model? Which model authors have used “The Weibel model and the Horsfield model.”
3. Will the human airways expand while the inhalation or exhalation process? If so, one has to model this as FSI. Can authors show clearly that the walls can modeled as rigid wall? If one has modeled as a rigid wall, what is inaccuracy involved in the solution
4. One the most important aspect of the CFD modeling to validation of the numerical model proposed. It is essential for the authors look at the validation like “ Zhao and Lieber “Steady inspiratory flow in a model symmetric bifurcation” J. Biomech. Eng., 116 (4) (1994), pp. 488-496”. I observed this for review article given in the list comment 1.
5. The authors are supposed to show grid independence and time step independence of the results
6. What was time step size used in this work. It known factthat OpenFOAM one used max Courant Number. The used settings are not completely specified.
7. The grid resolution for the various section should be depicted in figure
8. At which sections are the results presented in figure 4. It needs to be clarified in the text. Is the velocity profile symmetric? If not why authors want represent flow using a line data?
9. Over how many cycles is this Umean averaged for?
Author Response
Dear Reviewer,
Please see the attachment.
Best Regards
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Accept as it is
Reviewer 2 Report
The manuscript can be accepted in the current form
