Study on Wind Load Characteristics and Wind-Induced Response of Supertall Buildings with Single-Sided Large-Span Straight Platforms

Round 1

Reviewer 1 Report

Dear Authors, 

The present manuscript uses the Reynolds-averaged Navier-Stokes (RANS) method in Computational Fluid Dynamics (CFD) to investigate the surface wind pressure, gas bypassing phenomena and wind-induced vibrations in a target building by varying the wind direction and comparing some of these parameters with a reference model. The paper presents interesting results for future analyses, which may serve as a basis for future applications in different locations. In my opinion, this manuscript requires major revision, and the following issues should be considered/clarified prior to acceptance. I suggest a major revision.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

·               In the abstract, you should be mentioning the name of the abbreviation before writing the abbreviations.

·             Highlights should be improved. No more than 85 characters and no abbreviations. The current highlights are not meaningful.

·             The Conclusions and Abstract should be also expanded and contain more data of performed research results.

·             The equations should be cited. Below papers can help you:

·             Please explain more about the novelty of your work.

·             Some of the references are very old, and therefore, they are abolished. May the reviewer ask the authors to change these references to newer ones?

·             Some grammar, format consistency, and typing mistakes in the main body, as well as typing mistakes in the reference. The author should check the paper carefully once again. Application of double glazed façades with horizontal and vertical louvers to increase natural air flow in office buildings An experimental study on airborne particles dispersion in a residential room heated by radiator and floor heating systems Parametric investigation of thermal characteristic in trapezoidal cavity receiver for a linear Fresnel solar collector concentrator

Author Response

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Reviewer 3 Report

- P2, L52: Capitalize the first letter in each word for the terminology.

- P2, L64: This reviewer recommends adding a paragraph at the end of the introduction section to present the manuscript layout.

- P2, L75-89: Are there any calculations behind these values or do the authors just assume it?

- Enlarge figure 3 for better readability.

- It will be challenging to read figures 4 & figure 5(almost all contour map figures) in white and black printing. Is it possible to improve the readability of these figures?

- Increase the size of figures 6 & 7

- Change the texture for Figure 8 to improve the readability of the figure.

- Adjust the shift of figure 14 & figure 15.

 

- P14, L342: what is the name of the program used? Add more information about the analyzed models.

Author Response

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Reviewer 4 Report

 

1.      Please provide more detailed descriptions of the methods used in the article.

2. Please compare the calculation of multiple grids to verify the grid independence. And give the Y+value of the wall.

3.      Is there a basis for the choice of wind direction in the paper?

4.      Please clarify the reasons for the article's analysis of vortex shedding in partial wind directions only.

5.      Further clarification is needed on the displacement and acceleration response calculations in the article.

6.      The conclusion should summarize the results of the simulations in each part of the article and should contain more research results.

 

 

Author Response

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Reviewer 5 Report

The paper numerically examines the influence of the presence of the large-span straight platforms on the wind load characteristics and the wind induced response of the super tall buildings, based on Reynolds-averaged Navier-stokes (RANS) simulations. The CFD simulations in this article are not well validated, and the results and discussions in this study has some significant limitations. The detailed comments are as follows

:

Section 2: CFD numerical modelling and validation

1. Line 124 page3, “10 boundary layers on the building surface with a growth rate of 1.1.”

The growth rate value of the boundary layers, 1.1 seems to be larger than the commonly accepted value, i.e., 1.05, which could lead to a decrease of the accuracy of simulation. The Y+ plus value should be given here and a verification of the mesh independency is needed.

 

2. Line 134 page 4, “The dimension of the calculation domain are 900m×1400m×600m”

This indicates that the numerical model in this study is full-scale. And the accuracy of such full-scale simulation is hard to guarantee, due to the large value of the Reynolds number. The Reynolds number characteristics of the building model in this study should be demonstrated.

 

3. Line 148 page 5, “Outflow is used for the outlet boundary condition type…surface of the building model is Wall.”

The description of the meanings of the boundary layers, i.e., “Outflow”, “Symmetry” and “Wall” should be given.

 

4. Line 151-153 page5. “Seven measurement points of different heights were…as shown in Figure 2.”

The turbulence length scale and the wind spectrum should be given.

 

5. Line 153-156 page5. “A comparison of the wind pressure… agree well with the experimental results”.

The definition of the wind pressure coefficients Cp should be given. The Cp shows in Figure 3 is ambiguous, since we don’t know whether it is the mean pressure coefficient or the fluctuating pressure coefficient, though it seems to be the mean pressure results. For the validation of the numerical model, both the mean pressure coefficient and the fluctuating pressure coefficient, especially the latter, should be given, since the wind induced response of the building is significantly influenced by the fluctuating pressure. Moreover, it seems that all the results in this study is obtained based on steady simulations rather than unsteady simulations, which should be also be noted. The accuracy of the fluctuating pressure on the building is more difficult to satisfy than the mean pressure in steady RANS simulations. As a result, the CFD simulations in this article are not well validated and not convincing.

 

Section 3 Analysis of results and discussion

6. 3.1 Figs 4-7 and Figs 9-10.

The pressure coefficient results shown in Figs 4-7 seem to be the mean pressure coefficient, and the flow filed results in Figs 9-10 seem to be the mean flow field results, these should be noted. Only the mean wind induced results are investigated in the article, this should be emphasized in the tittle, abstracts and introduction part. Moreover, compared with the mean results, the fluctuating results, which are not discussed in this study, are more important for the design, construction, and safety assessment of supertall buildings. This may be because that only the mean results can be well obtained with steady RANS simulations. Thus, unsteady LES simulations, rather than RANS, are more recommended for this study from this point of view. Therefore, this study is not that significant for the engineering practices.

 

7. Line 252-265, page10. “Figure 8 shows the frequency of vortex shedding cycles for the two building models…when the incoming velocity and wind direction are the same.”

The time history and the spectral of the lift forces on the building should be given, without which the vortex shedding frequency results shown in Fig 8 are not that convincing.

 

8. Line 300-301, page 12. “The maximum and minimum values of the crosswind and downwind base moments…are shown in Figure 11 and Figure 12.”

The definition of the maximum and minimum values of the crosswind and downwind base moments should be given.

 

9. Line 344, page 14. “Therefore, it is more likely that the CMA and CMD reach…the correlation between the two is stronger.”

The definitions of the CMA and CMD values should be given.

 

10. Line 406-409, “For supertall buildings, the structural response is mainly derived from first-order…obtained as follows”

The results of the displacement response of the building is obtained based on the wind load obtained from the RANS simulations, since the fluctuating load results are not that accurate, the deviation of the calculated displacement should be evaluated.

Author Response

Dear reviewer, we appreciate your constructive comments and suggestions on our manuscript. We have carefully studied the comments and made our best efforts to improve the manuscript according to the comments. Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Study on wind load characteristics and wind induced response of supertall buildings with single-sided large-span straight platforms

The present manuscript uses the Reynolds-averaged Navier-Stokes (RANS) method in Computational Fluid Dynamics (CFD) to investigate the surface wind pressure, gas bypassing phenomena and wind-induced vibrations in a target building by varying the wind direction and comparing some of these parameters with a reference model. The paper presents interesting results for future analyses, which may serve as a basis for future applications in different locations. The authors did all recomendations and sugestions proposal making the paper better. Thus, I suggest Accept in present form.

Author Response

Dear reviewer, we appreciate your constructive comments and suggestions on our manuscript. Your suggestions have improved our article considerably. Thanks for your approval of the article as well. Finally, thanks again for the hard work of the reviewer!

Reviewer 4 Report

The author has revised the manuscripte according to the review comments.

Reviewer 5 Report

There is no more comments for the revised manuscript.