Application of Airfoil Arrays on Building Façades as a Passive Design Strategy to Improve Indoor Ventilation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study investigates the potential of grouped airfoil arrays as a passive design strategy to improve natural ventilation and indoor air quality in high-rise buildings, aiming to overcome the limitations of conventional air conditioning systems. The authors employed CFD simulations and field measurements to evaluate the performance of symmetrical, semi-symmetrical, and flat-bottom airfoil configurations on building facades.

Several points should be revised before the manuscript can be considered for final acceptance:

1. Abstract: The abbreviation ACH in line 16 should be spelled out in full at its first appearance in the abstract.
2. Lines 30-31: The statement “It accounts for around 60% of residential and nearly 50% of commercial buildings” contains inaccurate percentages. Please verify and correct these figures using up-to-date and reliable sources.
3. Equation (1): The equation appears prematurely at line 61, whereas the first contextual mention of it is in line 321. Please relocate the equation to a more appropriate position within the manuscript. Additionally, the variables in the equation lack definitions. Each notation should be clearly defined in the corresponding paragraph.
4. Table 1: The font size within the embedded figure is too small to read comfortably. Please enlarge the font for better readability. The same issue applies to Figures 1, 2, 3, and 9.
5. Figure 6: The figure on the right side lacks sufficient detail and should be enlarged or zoomed in to improve clarity and legibility.
6. Table 2: The reviewer recommends including a top view of the airfoil to better highlight the shape differences, particularly between the semi-symmetrical and symmetrical types. Additionally, the current graphical representation does not accurately reflect the true geometry of the airfoils used, especially in terms of the chord-to-height ratio. Please revise the figure to reflect the actual dimensions used in the study.
7. Figure 7: There is a formatting error in the figure caption. It appears to be merged with subsection 2.4 and its subtitle. Please correct this formatting issue for clarity.
8. Lines 246-247: It is unclear whether the data presented is based on a single measurement taken on the specified date. If this is the case, the dataset is insufficient to ensure reliability due to potential temporal fluctuations in environmental conditions. The authors should clarify whether multiple measurements were taken over a period of time and explain how the data was validated or averaged. Furthermore, the exact location of the field measurement should be clearly stated to allow proper interpretation and replication.
9. Line 262: The statement, “As shown in this table, air velocity of the points is the same for fine and the finest meshes,” is inaccurate. Table 4 shows noticeable differences between the mesh levels. Please revise the statement to reflect the actual data shown.
10. Lines 265-267: This section should be removed.
11. Table 4: The number of mesh cells used in each simulation must be included in Table 4. This information is essential to help readers assess the mesh sensitivity and the adequacy of the mesh resolution used in the CFD simulations.
12. The experimentally measured velocity data presented shows values below 0.15 m/s. However, according to widely available technical specifications, the velocity sensor used in this study typically operates within the range of 0.15–10 m/s. This discrepancy raises concerns about the reliability and accuracy of the validation data. If the sensor is not capable of detecting airflow velocities below 0.15 m/s with acceptable precision, the resulting validation may be flawed, weakening the credibility of the CFD validation and subsequent conclusions.
13. Subsection 3.3 is not included in the manuscript. Please clarify whether it was mistakenly omitted or misnumbered.
14. The term “velocity ratio” is frequently referenced in the paper but is never formally defined. A clear and concise definition should be provided in the manuscript to ensure readers fully understand its meaning and significance in the context of the study.
15. Figure 9: The placement of Figure 9 is too far from its first mention in the manuscript, which disrupts the flow of reading. Please move the figure closer to its initial reference to enhance coherence. Furthermore, the current setting of the color gradient uses a maximum value that is too high. As a result, the velocity distribution across different areas (e.g., balcony, living room, study room) is displayed in a uniform color, making it difficult to observe meaningful differences. To improve the interpretability of the figure, the gradient scale should be adjusted to better reflect subtle velocity variations.
16. Line 320: The reference to the table is incorrect. It should read “Table 6.” Please revise accordingly.
17. Table 6: It is recommended to add a column indicating the airfoil type, as presented in Table 2, for consistency and better clarity. Some cell border lines are missing, which affects the table’s readability. Please ensure consistent formatting throughout. The unit “m³/h” represents a volumetric flow rate, not velocity. However, in the table, it is mistakenly referred to as velocity. Please correct this error.
18. Additionally, the reviewer suggests summarizing the data in Table 6 using a graphical format (e.g., bar or line graph) to facilitate interpretation and comparison of results.
19. Line 360: A reference to a table is made, but the table number is missing. Please correct this omission for clarity.
20. The terms “air velocity ratio,” “wind velocity ratio,” and “air ratio” appear in the manuscript but are not clearly defined or differentiated. This creates confusion for the reader. The authors are strongly encouraged to review these terms and provide clear, consistent definitions in the appropriate section(s) of the manuscript.
21. The conclusion is currently presented as a single, lengthy paragraph, which may hinder readability. The reviewer recommends reformatting the conclusion into concise, point-form statements to enhance clarity, highlight key findings, and improve accessibility for readers.
22. The manuscript contains several writing issues, including repeated similar statements. These affect the overall fluency and clarity of the text. A thorough proofreading and language revision is highly recommended prior to final submission.

Author Response

Please note that all changes are in blue color in the revised manuscript.

Reviewer # 1

This study investigates the potential of grouped airfoil arrays as a passive design strategy to improve natural ventilation and indoor air quality in high-rise buildings, aiming to overcome the limitations of conventional air conditioning systems. The authors employed CFD simulations and field measurements to evaluate the performance of symmetrical, semi-symmetrical, and flat-bottom airfoil configurations on building facades.

Several points should be revised before the manuscript can be considered for final acceptance:

 

Comment 1: Abstract: The abbreviation ACH in line 16 should be spelled out in full at its first appearance in the abstract.   

Response: Thank you for comment. It is revised. Please see page 1, line number 20 in the revised manuscript.

 

Comment 2: Lines 30-31: The statement “It accounts for around 60% of residential and nearly 50% of commercial buildings” contains inaccurate percentages. Please verify and correct these figures using up-to-date and reliable sources.    

Response: Thank you. The figures are corrected using up-to-date and reliable sources. Please see page 1, line numbers 33 to 37 in the revised manuscript.          

Comment 3: Equation (1): The equation appears prematurely at line 61, whereas the first contextual mention of it is in line 321. Please relocate the equation to a more appropriate position within the manuscript. Additionally, the variables in the equation lack definitions. Each notation should be clearly defined in the corresponding paragraph.     

Response: Thank you for this comment. The equation has been relocated to an appropriate position, and definitions have been added afterward. Please check the page 21, line numbers 358 to 360 in the revised manuscript.

Comment 4: Table 1: The font size within the embedded figure is too small to read comfortably. Please enlarge the font for better readability. The same issue applies to Figures 1, 2, 3, and 9. 

Response: Thank you for this constructive comment. The font size within the embedded figures in table 1 has been corrected. Please see table 1 and figures in pages 4 to 9 in the revised manuscript.

Comment 5: Figure 6: The figure on the right side lacks sufficient detail and should be enlarged or zoomed in to improve clarity and legibility.      

Response: Figure 6 has been corrected as per request. Please see page 13, line number 184 in the revised manuscript.

Comment 6: Table 2: The reviewer recommends including a top view of the airfoil to better highlight the shape differences, particularly between the semi-symmetrical and symmetrical types. Additionally, the current graphical representation does not accurately reflect the true geometry of the airfoils used, especially in terms of the chord-to-height ratio. Please revise the figure to reflect the actual dimensions used in the study.       

Response: Thank you for comment. In order to highlight the shape difference, figure 7 is added in page 14, line number 210 in the revised manuscript. Please note that there is no difference in the ratio and It is constant in all designs.

Comment 7: Figure 7: There is a formatting error in the figure caption. It appears to be merged with subsection 2.4 and its subtitle. Please correct this formatting issue for clarity.

Response: Thank you. It is corrected in the revised manuscript. Please see page 17 line number 237.

Comment 8: Lines 246-247: It is unclear whether the data presented is based on a single measurement taken on the specified date. If this is the case, the dataset is insufficient to ensure reliability due to potential temporal fluctuations in environmental conditions. The authors should clarify whether multiple measurements were taken over some time and explain how the data was validated or averaged. Furthermore, the exact location of the field measurement should be clearly stated to allow proper interpretation and replication.

Response: The study conducted multiple measurements to ensure reliability of collected data. Moreover, in order to collect data for purpose of validation, the data were collected over a 30-minute period in the afternoon—when outdoor and indoor conditions were relatively stable. The authors add all these conditions in page 18, line numbers 266 to 273 in the revised manuscript.

Comment 9: Line 262: The statement, “As shown in this table, air velocity of the points is the same for fine and the finest meshes,” is inaccurate. Table 4 shows noticeable differences between the mesh levels. Please revise the statement to reflect the actual data shown.   

Response: The statement is revised to reflect the actual data. Please see in page 19, line numbers 293 to 297 in the revised manuscript.

Comment 10: Lines 265-267: This section should be removed.       

Response: Thank you for comment. The section is removed in the revised manuscript.

Comment 11: Table 4: The number of mesh cells used in each simulation must be included in Table 4. This information is essential to help readers assess the mesh sensitivity and the adequacy of the mesh resolution used in the CFD simulations.

Response: Thank you for constructive comment. It was already done during the simulation. However, the authors forgot to present them in the manuscript. So, the mesh numbers have been added in the table 4 in the revised manuscript. It was based on the study by Celik (2004). The study recommends the grid refinement ratio to be greater than 1.3 to allow the discretization error to be determined from the other sources of error.

Comment 12: The experimentally measured velocity data presented show values below 0.15 m/s. However, according to widely available technical specifications, the velocity sensor used in this study typically operates within the range of 0.15–10 m/s. This discrepancy raises concerns about the reliability and accuracy of the validation data. If the sensor is not capable of detecting airflow velocities below 0.15 m/s with acceptable precision, the resulting validation may be flawed, weakening the credibility of the CFD validation and subsequent conclusions. 

Response: Thank you for your valuable comment. The velocity sensor used in this study was the T-DCI-F900-S-O, which is designed for indoor airflow monitoring. Although the manufacturer specifies a standard operational range of 0.15–10 m/s, in practice, the sensor is capable of detecting velocities below 0.15 m/s with reduced accuracy, depending on environmental stability and signal averaging.

To ensure reliability, multiple readings were recorded at each point and time-averaged to minimize noise. Furthermore, a sensitivity analysis was conducted to confirm that potential measurement uncertainty in the sub-0.15 m/s range does not significantly affect the CFD validation results. The close agreement between measured and simulated values (as shown in Tables 4 and 5) supports the robustness of our data and conclusions.

In addition to the standard sensor (T-DCI-F900-S-O), we conducted a supplementary test using a high-precision hot-wire anemometer to verify airflow measurements below 0.15 m/s. The comparison confirmed that the values reported by the T-DCI sensor in the 0.04–0.15 m/s range were within an acceptable deviation (±8%), confirming the validity of the experimental data.

A calibration procedure was conducted using a hot-wire anemometer, TSI VelociCalc 9545, to validate the accuracy of the T-DCI-F900-S-O sensor at low airflow velocities (0.04–0.15 m/s). The results showed good agreement, with an average deviation of less than ±8%. Therefore, the experimental measurements reported in this study are considered valid for CFD validation.

Additional clarification about the sensor’s characteristics and our measurement procedure has been added to page 16, line numbers 227 to 234 in the revised manuscript.

Comment 13: Subsection 3.3 is not included in the manuscript. Please clarify whether it was mistakenly omitted or misnumbered.

Response: The subsections have been revised and corrected as per requested. Thank you for comment.

Comment 14: The term “velocity ratio” is frequently referenced in the paper but is never formally defined. A clear and concise definition should be provided in the manuscript to ensure readers fully understand its meaning and significance in the context of the study. 

Response: Thank you for comment. The velocity ratio is changed to air velocity. The air velocity is referred to as the rate at which air moves in a specific direction, typically measured in meters per second.

Comment 15: Figure 9: The placement of Figure 9 is too far from its first mention in the manuscript, which disrupts the flow of reading. Please move the figure closer to its initial reference to enhance coherence. Furthermore, the current setting of the color gradient uses a maximum value that is too high. As a result, the velocity distribution across different areas (e.g., balcony, living room, study room) is displayed in a uniform color, making it difficult to observe meaningful differences. To improve the interpretability of the figure, the gradient scale should be adjusted to better reflect subtle velocity variations.     

Response: Thank you for your constructive comment. The figure is moved closer to its initial reference to enhance coherence.

A maximum value for the gradient has been selected to present the outdoor air velocity at different points precisely. By changing the gradient, the problem cannot be solved. In order to respond to the comment properly, we decided to add indoor simulation results, which show the air velocity distribution across different areas. The difference in air velocity and pattern among spaces is meaningful, as shown in Figure 10 (b). Please note that figure 9 is changed to figure 10 (a) and (b) in the revised manuscript.

Comment 16: Line 320: The reference to the table is incorrect. It should read “Table 6.” Please revise accordingly.

Response: It is corrected in the revised manuscript.

Comment 17: Table 6: It is recommended to add a column indicating the airfoil type, as presented in Table 2, for consistency and better clarity. Some cell border lines are missing, which affects the table’s readability. Please ensure consistent formatting throughout. The unit “m³/h” represents a volumetric flow rate, not velocity. However, in the table, it is mistakenly referred to as velocity. Please correct this error.         

Response: Thank you for constructive comment. A column has been added to present airfoil type in the revised manuscript. Moreover, all recommended changes have been applied in table 6 for better readability. Please see table 6 in pages 22 and 23 in the revised manuscript.

Comment 18: Additionally, the reviewer suggests summarizing the data in Table 6 using a graphical format (e.g., bar or line graph) to facilitate interpretation and comparison of results.       

Response: Thank you for comment. Figure 8 has been added to summarize the data. Please see page 24 in the revised manuscript.

Comment 19: Line 360: A reference to a table is made, but the table number is missing. Please correct this omission for clarity.        

Response: It has already had a number! The authors checked again in the revised manuscript.

Comment 20: The terms “air velocity ratio,” “wind velocity ratio,” and “air ratio” appear in the manuscript but are not clearly defined or differentiated. This creates confusion for the reader. The authors are strongly encouraged to review these terms and provide clear, consistent definitions in the appropriate section(s) of the manuscript.         

Response:  In order to be consistent and clear, all terms are changed to air velocity. The air velocity is referred to as the rate at which air moves in a specific direction, typically measured in meters per second. Also, the wind ratio is changed to wind speed.

Comment 21: The conclusion is currently presented as a single, lengthy paragraph, which may hinder readability. The reviewer recommends reformatting the conclusion into concise, point-form statements to enhance clarity, highlight key findings, and improve accessibility for readers.

Response: Thank you for your valuable comment. It is revised based on your suggestions. Please see page numbers 25- and 26-line numbers 439 to 470 in the revised manuscript.

Comment 22: The manuscript contains several writing issues, including repeated similar statements. These affect the overall fluency and clarity of the text. A thorough proofreading and language revision is highly recommended before final submission.           

Response: Thank you for comment. In order to improve the fluency and clarity of the text, proofreading and language revision have been done for all parts of manuscript. The repeated statements have been removed especially in introduction and conclusion in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Article title: Application of airfoil arrays on building façade as a passive design 2 strategy for improvement of indoor ventilation

The article presents an interesting and valuable topic; however, here are some suggestions to enhance its quality:

1. The illustration labeled “Passive ventilation type: Primary method of natural ventilation in domestic buildings” in Table 1 has been widely used in various articles and books. Therefore, please provide an appropriate citation for it.
2. In Table 1, the second column would be more coherent if all rows were accompanied by relevant figures, as is already done in the first and third rows. Consider adding figures for consistency and clarity.
3. The caption for Figure 1 is unclear. It is recommended to revise the title and explicitly mention that the building depicted is the case study used in this research.
4. It would strengthen the study significantly to include field validation data for at least one of the airfoil array configurations, to allow comparison with the simulated results. If this is not feasible, provide a stronger justification for relying exclusively on CFD.
5. Include a parametric analysis or discussion of the effects of varying wind directions and speeds. This would also support the generalizability of the findings to non-tropical climates and help clarify any limitations.
6. The study does not address possible negative impacts of installing airfoil arrays, such as aesthetic disruption to façades or structural load/integration challenges. A discussion of these aspects would enhance the practical relevance of the research.
7. It is important to explain how the proposed grouped airfoils differ from conventional elements such as fins or louvers, both in form and function. This will help emphasize the novelty and contribution of the research.

 

Author Response

Please note that all changes are in blue color in the revised manuscript.

Reviewer # 2:

The article presents an interesting and valuable topic; however, here are some suggestions to enhance its quality:

Comment 1: The illustration labeled “Passive ventilation type: Primary method of natural ventilation in domestic buildings” in Table 1 has been widely used in various articles and books. Therefore, please provide an appropriate citation for it.          

Response: Thank you for your valuable comment. Appropriate citations have been added for columns 2 and 3 of table 1 in the revised manuscript. References from 20 to 51 are referred to contents of table 1 in the revised manuscript.

Comment 2: In Table 1, the second column would be more coherent if all rows were accompanied by relevant figures, as is already done in the first and third rows. Consider adding figures for consistency and clarity.    

Response: Thank you for your constructive comment. Based on your suggestion, all rows were accompanied by relevant figures in table 1 in the revised manuscript.

Comment 3: The caption for Figure 1 is unclear. It is recommended to revise the title and explicitly mention that the building depicted is the case study used in this research.           

Response: Thank for comment. It is corrected based on the suggestion. Please see page 11 line number 137 in the revised manuscript.

Comment 4: It would strengthen the study significantly to include field validation data for at least one of the airfoil array configurations, to allow comparison with the simulated results. If this is not feasible, provide a stronger justification for relying exclusively on CFD.    

Response: Thank you for the comment. For validation purposes, the numerical simulation results have been compared with full-scale measurements in section 3.2. As it is shown in table 5, the predicted results by the simulation at all 10 points in the selected unit are in good agreement with the measured data. Thus, the study does not rely solely on CFD results. The reliability of results from the program was evaluated by real full-scale measured data before evaluation of different types of airfoils. Scientifically, there are many published studies that apply this procedure for the purpose of validation. Here are some examples;

Chen, C., & Gorlé, C. (2022). Full-scale validation of CFD simulations of buoyancy-driven ventilation in a three-story office building. Building and Environment, 221, 109240.

Hu, H., Kikumoto, H., Ooka, R., Lin, C., & Zhang, B. (2022). Comprehensive validation of experimental and numerical natural ventilation predictions based on field measurements with an experimental house. Building and Environment, 207, 108433.

Iskandar, L., Bay-Sahin, E., Martinez-Molina, A., & Beeson, S. T. (2024). Evaluation of passive cooling through natural ventilation strategies in historic residential buildings using CFD simulations. Energy and buildings, 308, 114005.

Bay, Ezgi, Antonio Martinez-Molina, and William A. Dupont. "Assessment of natural ventilation strategies in historical buildings in a hot and humid climate using energy and CFD simulations." Journal of Building Engineering 51 (2022): 104287.

For a stronger justification and in order to consider your constructive comment, the above-mentioned studies have been added in the revised manuscript, line numbers 306 to 307.

Moreover, the construction of airfoil arrays is one of the limitations of this study, as it takes time and money to make an evaluation model. Furthermore, the test needs a wind tunnel, which is not available during this study.

Comment 5: Include a parametric analysis or discussion of the effects of varying wind directions and speeds. This would also support the generalizability of the findings to non-tropical climates and help clarify any limitations.         

Response: Thank you for your comment. The main focus of this study was to evaluate different shapes of airfoils, including flat-bottom, semi-symmetrical, and symmetrical, to identify the best design (in terms of quantity and shape) for maximum ventilation efficiency in buildings. Thus, other parameters, including environmental and non-environmental conditions, were kept constant to understand the pure effects of shape on ventilation. Furthermore, the study focused on the air gap between the symmetrical airfoil to find out the best distance (according to the Venturi effect) for maximum air velocity and ACH in a building. Although wind direction and speed as environmental conditions impact the efficiency of airfoils in providing different air velocities, this issue was not within the scope of this study. That’s why in the last paragraph of the conclusion; the authors recommend further studies on the effects of wind speed and direction on symmetrical triple airfoils (the main finding of the current study) in future research.

Moreover, the results of the study can be generalized for non-tropical climates, whereas differences in temperature and humidity could not impact on Brunelli’s rule and the venturi shape of grouped airfoils. Future studies can apply the main findings of this study (symmetrical triple airfoils) and focus on other design parameters, including environmental and non-environmental, to maximize ventilation efficiency in a non-tropical climate.

Comment 6: The study does not address possible negative impacts of installing airfoil arrays, such as aesthetic disruption to façades or structural load/integration challenges. A discussion of these aspects would enhance the practical relevance of the research.        

Response: Thank you for this valuable comment. The following statement has been added in the revised manuscript at page 14, line numbers 196 to 208.

 Although the installation of airfoil arrays increases the ACH in the residential units, some negative impacts need to be addressed. For instance, an unsuitable location on the building façade for the installation could impact aesthetic values. In order to enhance the practicability of this concept, parapet B has been selected for this study (See figure 4). The proper location allows the airfoil arrays to be installed on the building façade without blocking the views from inside and preventing sun rays from penetrating the residential unit. Furthermore, the aesthetic values of the building façade were not baffled and disregarded.

Furthermore, to create airfoils practically from the primary concept and theory, the selection of the most relevant material plays a crucial role according to the cost-effectiveness and structural load. Therefore, the feasible and achievable material for grouped airfoil slices was investigated in the study based on certain essential parameters. Light-weight, durability, flexibility, and adjustability to the space and cost-effectiveness were crucial factors in the selection of material. Based on these factors, the study recommended three types of composites, including fiberglass, Wood Plastic Composite (WPC), and caoutchouc, besides aluminum, as applicable materials for the formation of slices of airfoils on the external surface of the building façade.

Comment 7: It is important to explain how the proposed grouped airfoils differ from conventional elements such as fins or louvers, both in form and function. This will help emphasize the novelty and contribution of the research.

Response: Thank you for this constructive comment. The novelty of this idea can be addressed as below. A paragraph has been added to emphasize the novelty and contribution of the research. Please see page no 26 Line numbers 444 to 454 in the revised manuscript.

In this study, the proposed airfoil-shaped elements differ fundamentally from conventional fins or louvers both morphologically and aerodynamically. While traditional louvers or fins typically employ planar, rectilinear geometries designed primarily for solar shading or visual screening, the airfoil profiles introduced in this study are derived from aerodynamic principles and are shaped to reduce drag, guide airflow, and enhance pressure differentials across the façade.

Functionally, conventional louvers are generally optimized for controlling solar radiation and providing limited directional ventilation. In contrast, the grouped airfoil arrays in this research are explicitly configured to manipulate airflow patterns and promote indoor air exchange through passive means. CFD simulation results (see Table 6) demonstrate that these profiles induce significant pressure and velocity variations at the inlet, thereby generating higher volumetric airflow rates and improved air change per hour (ACH) values compared to standard planar systems. For example, Design No. 5 achieved a volumetric flow of 2750 m³/h and an ACH of 23, significantly outperforming other geometries.

Moreover, unlike conventional louvers, the airfoil arrays are deployed in a grouped configuration with staggered orientation and spacing, deliberately engineered to exploit the pressure-driven ventilation. This design facilitates enhanced airflow entrainment and mixing, which is critical in improving natural ventilation in urban environments with low wind speeds or polluted air.

Thus, the proposed system not only redefines the formal language of building-integrated airflow devices but also introduces a performance-driven approach rooted in aerodynamic optimization, which is currently underexplored in architectural applications.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript explores an innovative approach to improving natural ventilation in high-rise residential buildings by using grouped airfoil arrays on building façades. The topic is relevant and timely, especially in the context of sustainable and passive design strategies. However, the paper requires major revision due to the following issues:

Language and Clarity: The English needs significant improvement. There are many grammatical errors and unclear sentences that make the paper hard to follow.

Repetition: The introduction and conclusion repeat several ideas unnecessarily.

Limited Methodology Description: The CFD simulation setup lacks essential details such as boundary conditions, mesh size, or validation method.

Narrow Scope of Simulation: Only one wind speed is studied. For broader applicability, the impact of different wind speeds and directions should be considered.

Data Presentation: The numerical results are difficult to interpret without graphs, tables, or visuals. Units should be used consistently.

The concept is strong, but the manuscript needs clearer writing, more methodological detail, and improved result presentation to be publishable.

Comments for author File: Comments.pdf

Author Response

Please note that all changes are in blue color in the revised manuscript.

Reviewer # 3

This manuscript explores an innovative approach to improving natural ventilation in high-rise residential buildings by using grouped airfoil arrays on building façades. The topic is relevant and timely, especially in the context of sustainable and passive design strategies. However, the paper requires major revision due to the following issues:

Comment 1: Language and Clarity: The English needs significant improvement. There are many grammatical errors and unclear sentences that make the paper hard to follow.

Response: Thank you for comment. In order to improve the fluency and clarity of the text, proofreading and language revision have been done for all parts of manuscript. Grammatical errors and unclear statement have been removed or corrected in the revised manuscript.

Comment 2: Repetition: The introduction and conclusion repeat several ideas unnecessarily.

Response: Thank you for your valuable comment. The repeated statements have been removed especially in introduction and conclusion in the revised manuscript.

Comment 3: Limited Methodology Description: The CFD simulation setup lacks essential details such as boundary conditions, mesh size, or validation method.   

Response: Thank you for raising this issue. In section 2.4.1 in the revised manuscript, an explanation regarding boundary conditions and grid generation has been added completely. Also, the total number of generated meshes has been presented in Table 4. Moreover, model validation is presented in section 3.2, whereas the results of full-scale measurement are compared with numerical simulation. The predicted results by the simulation at all points are in good agreement with the measured data.

Please let the authors know in case we should add further information.

Comment 4: Narrow Scope of Simulation: Only one wind speed is studied. For broader applicability, the impact of different wind speeds and directions should be considered.           

Response: Thank you for your comment. The main focus of this study was to evaluate different shapes of airfoils, including flat-bottom, semi-symmetrical, and symmetrical, to identify the best design (in terms of quantity and shape) for maximum ventilation efficiency in buildings. Thus, other parameters, including environmental and non-environmental conditions, were kept constant to understand the pure effects of shape on ventilation. Furthermore, the study focused on the air gap between the symmetrical airfoil to find out the best distance (according to the Venturi effect) for maximum air velocity and ACH in a building. Although wind direction and speed as environmental conditions impact the efficiency of airfoils in providing different air velocities, this issue was not within the scope of this study. That’s why in the last paragraph of the conclusion; the authors recommend further studies on the effects of wind speed and direction on symmetrical triple airfoils (the main finding of the current study) in future research. Please see page number 27, line numbers 471 to 474 in the revised manuscript.

Moreover, the results of the study can be generalized for non-tropical climates, whereas differences in temperature and humidity could not impact on Brunelli’s rule and the venturi shape of grouped airfoils. Future studies can apply the main findings of this study (symmetrical triple airfoils) and focus on other design parameters, including environmental and non-environmental to maximize ventilation efficiency in a non-tropical climate.

Comment 5: Data Presentation: The numerical results are difficult to interpret without graphs, tables, or visuals. Units should be used consistently.          

Response: Thank you for your valuable comment. In order to present the numerical results properly, figures 10 and 11 have been added in the revised manuscript. Also, table 6 has been revised and a column has been added presenting the shape of airfoils and related results. Moreover, tables 7 and 8 show the results numerically and visually.  

Comment 6: The concept is strong, but the manuscript needs clearer writing, more methodological detail, and improved result presentation to be publishable.         

Response: Thank you for your valuable comment. In order to respond this comment properly, proofreading and language revision have been done for all parts of manuscript.

Methodological details including validation and calibration of devices have been added to present reliable results (Please see line numbers 283 to 294 and line numbers 227 to 234 and line numbers 266 to 297 in the revised manuscript). Moreover, for better interpretation, tables and figures have been added to improve the results presentation. (Please see tables 6, 7 and 8 and figures 10 and 11 in the revised manuscript.)

Author Response File: Author Response.docx