Impact of Modelling Surface Roughness in an Arterial Stenosis

Round 1

Reviewer 1 Report

The paper is devoted to account of inner surface roughness on the hemodynamics in stenosed artery. Several patient-specific geometries were used for CFD analysis. It was found that the flow was oscillatory downstream of the stenosis in the models. OSI, TAWSS, RRT and other metrics were used for analysis. The pressure distributions between the smooth and rough model did not vary significantly. The difference of the wall shear metrics was slight in the stenotic region and became larger in the downstream region of the models.   The paper is well-structured and contains contemporary results, which can be interesting for biomechanicians and clinicians.    Limitations and questions, which should be mentioned in manuscript body:

1. Why do the authors adopt CFD, but not FSI.
2. Unfortunately, the same boundary conditions are used for all geometries.
3. is patinent-specific inlet profile was taken from the patient with the same pathology?

Author Response

1. Why do the authors adopt CFD, but not FSI.

FSI is one of the most challenging areas in simulations. The limitation has been addressed at the end of the discussion (from Line 267). The compliant wall model and the deformation of the arterial wall may be included in the future.

2. Unfortunately, the same boundary conditions are used for all geometries.

There is only one patient-specific model in this study. Same boundary conditions are used to compare the difference between the models with and without the presence of the stenotic surface roughness.

3. is patient-specific inlet profile was taken from the patient with the same pathology?

Yes, the inlet profile was collected clinically from the patient (smooth model). Artificial roughness has been created and the same inlet boundary has been used to both smooth and rough models.

Reviewer 2 Report

The paper uses computational fluid dynamics to analyse the influence of geometrical distortions in arterial stenosis. The paper is generally well written and the results are of significant interest to the numerical modelling community focused on patient-specific models. The paper is recommended for publication subject to the following minor revisions.

1. Further proofreading is recommended to iron out occasional grammatical/sentencing errors.
2. Did the authors carry out a mesh convergence study? What were the responses monitored?
3. It is recommended that the authors present the boundary conditions used for the study in the form of a figure.
4. What sort of validation has been performed? How did the authors confirm the validity of the model?
5. What is the size of the model and how long did it take to run (solution time)?
6. Does figure 3 caption read zoom-in views? Are the authors referring to magnified views? If so please show an indicative scale?
7. What are the limitations of the study? Present the author's view in this regard?
8. Elaborate on the future scope and challenges.

 

Author Response

1. Further proofreading is recommended to iron out occasional grammatical/sentencing errors.

Amendments have been made throughout the whole article, which are tracked by the red-color texts.

2. Did the authors carry out a mesh convergence study? What were the responses monitored?

Yes, the mesh independency study has been presented from Line 133 to Line 140.

3. It is recommended that the authors present the boundary conditions used for the study in the form of a figure.

The inlet boundary profile is obtained from the patient clinically and presented in Figure 1C. Other fluid boundaries and flow properties are from previously published papers.

4. What sort of validation has been performed? How did the authors confirm the validity of the model?

This study is only a preliminary analysis. More patient-specific models and experimental validation can be performed in the future, which has also been added in the limitation & future study part (Line 275-278).

5. What is the size of the model and how long did it take to run (solution time)?

The element sizes have been presented in Line 135 & 136. High performance clusters have been used for the simulations. 96 core CPUs have been used and the calculation time for each model is around 5-6 weeks.

6. Does figure 3 caption read zoom-in views? Are the authors referring to magnified views? If so please show an indicative scale?

Yes, it is magnified views. The scale factor is 1:50 and has been added in captions of Figure 3.

7. What are the limitations of the study? Present the author's view in this regard?

Limitation and future scope are present in Line 268-278.

8. Elaborate on the future scope and challenges.

Limitation and future scope are present in Line 268-278.