Numerical Method to Determine the Inception of Propeller Tip Vortex Cavitation Based on Bubble Dynamics

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript proposes a numerical calculation method for predicting tip vortex cavitation inception. The proposed method is constructed based on the Eulerian-Lagrangian framework of describing the dynamics of bubbles, whose theory was set up on the established science and whose algorithm was implemented in a reliable manner. This manuscript should be revised further considering the following comments:

(1)   How were the governing equations numerically solved? More explanations should be provided on it.

(2)   In Figures 9-11, the cavitation numbers in the simulation should be set to be the same as those in the experiment.

(3)   How can this study show that the calculated numbers of incipient cavitation bubbles agreed closely with the experimental ones for the wider ranges of sigma?

Comments on the Quality of English Language

The writing English in this paper needs further improvments.

Author Response

Dear Editor and Reviewers:

On behalf of all the authors, I would like to thank you for your letter and the reviewers for their constructive comments on our paper titled "Numerical Method to Determine the Inception of Propeller Tip Vortex Cavitation Based on Bubble Dynamics" (Manuscript ID: applsci-2748341).

Please refer to the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

 

The article presents the implementation of a numerical model for cavitation prediction using the Eulerian-Lagrangian framework. The proposed method and developed criteria will be valuable for researchers and practitioners in the field.

 

Upon reading the article, I had some questions:

• The explanation of parameters used in eq. 11 must be included (epsilon, Pdot, c0, Pr=R).
• If the initial sizes of nuclei significantly influence the process, wouldn't it be adequate to study the sensitivity of the presented results on this parameter? 
• A common practice in CFD is to model a single-blade passage with periodic boundary conditions. Was there any reason to model the complete propeller?
• Can you explain why the location shown in Fig.4 has been chosen for particle release? What should you look out for when selecting the particle injection location? Such practical information would be valuable for other researchers using your method.
• What solver did you use? Can the developed calculation procedure code for Lagrangian phase be shared as a supplementary material?

 

Minor remarks and questions:

- HRL abbreviation is not explained 

- How does tracking the Lagrangian phase influence the calculation time over the classical Eulerian approach?

- Details of the boundary layer are unclear from the image; what is the number of layers and growth ratio?

- Lines 208-209 mention four forces, but eq. 6 describes only three forces; mass forces are missing.

- If Eqs. 1 and 2 describe incompressible RANS equations, then the time derivative of density on the LHS of eq. 1 should be zero; 

 

Otherwise, it is an excellent article.

 

Kind regards,

Reviewer

Comments on the Quality of English Language

I have some remarks regarding English, e.g. continuity equation (not continuous equation), turbulent viscosity (not turbulence viscosity), and the number of elements is set to 13,000,000 (not number of grids).

Author Response

Dear Editor and Reviewers:

On behalf of all the authors, I would like to thank you for your letter and the reviewers for their constructive comments on our paper titled "Numerical Method to Determine the Inception of Propeller Tip Vortex Cavitation Based on Bubble Dynamics" (Manuscript ID: applsci-2748341).

Please refer to the attached file.

Author Response File: Author Response.pdf