A Method to Evaluate Forchheimer Resistance Coefficients for Permeable Screens and Air Louvers Modelled as a Porous Medium

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review for: A Method to Evaluate Forchheimer Resistance Coefficients for Permeable Screens and Air Louvers Modelled as a Porous Medium

 

The paper analyses the use of properly defined momentum sinks/sources to model the presence of permeable elements. The topic is of actual and of great technical interest. The article is interesting to read and presents a substantial improvement with respect to the available literature. In particular, the provided analytical solutions can effectively guide the calibration of the Forchheimer resistance coefficients, which are otherwise selected disregarding their actual effect on the simulation, as correctly pointed out in the paper.

 

Some comments are provided below:

1) Eq. (13) might be made clearer. The FCV is equal to the sum of 4 contribution which are then equated to the inertial contribution. Maybe it is better to avoid the double equating (indeed FCV is unnecessary and only dynamic equilibrium is needed). Furthermore, the reviewer does not understand Eq. (14): the force over the screen should be by definition the pressure integral plus eventual viscous stresses. Maybe the reviewer is missing something here. Please revise this section carefully.

 

2) It would be interesting to discuss if there is any reason to assume that resistance, in general cases, shall allow a tensorial description. Despite this, the obtained result appears convincing, so it must be true at least as approximation. Insights on such regards might come also from recent literature which attempt to characterize resistance at the microscopic scale, see for instance [1].

3) Between similar approaches, it might be worth to mention that recently proposed in [2], which is expected to have similar capabilities, despite being based on the introduction of baffles.

[1] Granados-Ortiz, F. J., Ortega-Casanova, J., Lopez-Martinez, A., & Mahabaleshwar, U. S. (2023). Estimation of the aerodynamic tortuosity of woven/wire screens. Journal of Wind Engineering and Industrial Aerodynamics, 243, 105608.

[2] Xu, M., Patruno, L., & de Miranda, S. (2023). A pressure–velocity jump approach for the CFD modelling of permeable surfaces. Journal of Wind Engineering and Industrial Aerodynamics, 233, 105317.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In this research, the authors employed the least-square optimization to provide coefficients in proposed diagonal and non-diagonal Forchheimer tensors, and further applied to wind field problems porous media based on the Navier-Stokes (N-S) equations. This paper provided the mathematical descriptions of the proposed method and the description of the used solver. Furthermore, three examples are examined to validate the capability of the proposed method. In my opinion, the general structure of the paper is relatively comprehensive, it would be possible to publish after a minor revision considering all of the following comments.

1.          For existing methods, I think it is necessary to add citations in the description, rather than simply citing them in the literature review section.

2.          The authors mentioned that using RANs turbulence model for simulation for the wind field model. However, regarding the descriptions of Forchheimer tensors in the previous section of the paper, it is a bit confused that the proposed method was applied to general N-S equations or turbulence model? The authors need to reorganize and provide an explanation.

This research was based on the steady-state problems, I suggest that the authors can provide a simply comment about applying the proposed method for time-dependent problems.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf