Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2024.106004
E Deng , Xin-Yuan Liu , De-Hui Ouyang , Huan Yue , Yi-Qing Ni
High-speed trains (HSTs), traveling at speeds of up to 300 km/h, are subjected to safety risks in crosswind conditions, particularly when they enter or exit tunnels due to transient aerodynamic effects. The study employs a three-dimensional (3D) ultrasonic anemometer array positioned at the tunnel entrance to investigate the jet flow structure and its 3D characteristics that are induced by HSTs as they enter tunnels. The main results are as follows: The jet flow speed reaches approximately 3%–7% of the train's operational speed, with a maximum length of around 0.48 L. When the train speed is increased from 300 km/h to 400 km/h, the effect of its slipstream on the surrounding wind speed increases by 33% upon entering the tunnel, while in the jet flow section, the wind speeds from both sources are comparable. Through field measurement and numerical simulation, this study provides better understanding of the characteristics of the 3D jet flow structure generated from HSTs entering tunnels, thus offering more insight in developing means for reducing jet flows.
{"title":"3D ultrasonic anemometer array reveals jet flow structures at the entrance of high-speed railway tunnel","authors":"E Deng , Xin-Yuan Liu , De-Hui Ouyang , Huan Yue , Yi-Qing Ni","doi":"10.1016/j.jweia.2024.106004","DOIUrl":"10.1016/j.jweia.2024.106004","url":null,"abstract":"<div><div>High-speed trains (HSTs), traveling at speeds of up to 300 km/h, are subjected to safety risks in crosswind conditions, particularly when they enter or exit tunnels due to transient aerodynamic effects. The study employs a three-dimensional (3D) ultrasonic anemometer array positioned at the tunnel entrance to investigate the jet flow structure and its 3D characteristics that are induced by HSTs as they enter tunnels. The main results are as follows: The jet flow speed reaches approximately 3%–7% of the train's operational speed, with a maximum length of around 0.48 <em>L</em>. When the train speed is increased from 300 km/h to 400 km/h, the effect of its slipstream on the surrounding wind speed increases by 33% upon entering the tunnel, while in the jet flow section, the wind speeds from both sources are comparable. Through field measurement and numerical simulation, this study provides better understanding of the characteristics of the 3D jet flow structure generated from HSTs entering tunnels, thus offering more insight in developing means for reducing jet flows.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 106004"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143102857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2024.105969
Zihan Mahmood Nahian, Lee-Sak An, Pedro L. Fernández-Cabán, Sungmoon Jung
This paper presents the application of artificial neural networks (ANNs) for predicting mean wind profile characteristics over heterogeneous terrains. The ANN models integrate salient terrain features to predict the vertical wind profile structure of neutrally stable atmospheric boundary layer (ABL) flows. The research leveraged wind profile data collected in a large boundary layer wind tunnel equipped with a mechanized roughness element grid, which enabled the simulation of a wide range of heterogeneous terrain conditions. Three ANN architectures are examined to determine the most critical terrain features that influence wind profile prediction. Specifically, several input parameters are investigated to capture proximate and distal roughness changes upstream to the measurement location. The results demonstrate the efficacy of the proposed ANN-based approach in accurately predicting mean wind profiles over heterogeneous terrains. While the ANN models exhibit a higher degree of accuracy and reliability, they require large volumes of data that may not be easily accessible. However, the research findings will help advance predictive modeling in wind engineering and deepen our understanding of boundary layer physics by identifying key parameters and developing strategies to accurately capture wind profiles over complex heterogeneous terrains.
{"title":"Artificial neural networks for predicting mean wind profiles over heterogeneous terrains","authors":"Zihan Mahmood Nahian, Lee-Sak An, Pedro L. Fernández-Cabán, Sungmoon Jung","doi":"10.1016/j.jweia.2024.105969","DOIUrl":"10.1016/j.jweia.2024.105969","url":null,"abstract":"<div><div>This paper presents the application of artificial neural networks (ANNs) for predicting mean wind profile characteristics over heterogeneous terrains. The ANN models integrate salient terrain features to predict the vertical wind profile structure of neutrally stable atmospheric boundary layer (ABL) flows. The research leveraged wind profile data collected in a large boundary layer wind tunnel equipped with a mechanized roughness element grid, which enabled the simulation of a wide range of heterogeneous terrain conditions. Three ANN architectures are examined to determine the most critical terrain features that influence wind profile prediction. Specifically, several input parameters are investigated to capture proximate and distal roughness changes upstream to the measurement location. The results demonstrate the efficacy of the proposed ANN-based approach in accurately predicting mean wind profiles over heterogeneous terrains. While the ANN models exhibit a higher degree of accuracy and reliability, they require large volumes of data that may not be easily accessible. However, the research findings will help advance predictive modeling in wind engineering and deepen our understanding of boundary layer physics by identifying key parameters and developing strategies to accurately capture wind profiles over complex heterogeneous terrains.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 105969"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143162969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2024.105991
Xiangyan Chen, Takeshi Ishihara
In this study, an unsteady Reynolds-Averaged Navier-Stokes (URANS) model with a prespecified averaging time and a new method for turbulent inflow generation is proposed to predict turbulent flows over complex terrain. Firstly, the effect of grid resolution on turbulent flows over complex terrain is investigated by the Reynolds-Averaged Navier-Stokes (RANS) and the URANS models. URANS improves the accuracy of the predicted mean velocity and standard deviation by using finer grids, but the improvement by RANS is limited. Furthermore, the turbulent flows over hills with different slopes predicted by URANS are examined with respect to various averaging times. An optimal averaging time based on the slope of the hills is recommended considering the prediction accuracy and computational efficiency of URANS. Finally, turbulent flows over complex terrain in coastal areas are investigated by URANS and validated by wind tunnel tests. The predicted mean and standard deviation of streamwise velocity over complex terrain by URANS are in good agreement with the experimental data, while those by RANS are overestimated or underestimated.
{"title":"Numerical study of turbulent flows over complex terrain using an unsteady Reynolds-averaged Navier-Stokes model with a new method for turbulent inflow generation","authors":"Xiangyan Chen, Takeshi Ishihara","doi":"10.1016/j.jweia.2024.105991","DOIUrl":"10.1016/j.jweia.2024.105991","url":null,"abstract":"<div><div>In this study, an unsteady Reynolds-Averaged Navier-Stokes (URANS) model with a prespecified averaging time and a new method for turbulent inflow generation is proposed to predict turbulent flows over complex terrain. Firstly, the effect of grid resolution on turbulent flows over complex terrain is investigated by the Reynolds-Averaged Navier-Stokes (RANS) and the URANS models. URANS improves the accuracy of the predicted mean velocity and standard deviation by using finer grids, but the improvement by RANS is limited. Furthermore, the turbulent flows over hills with different slopes predicted by URANS are examined with respect to various averaging times. An optimal averaging time based on the slope of the hills is recommended considering the prediction accuracy and computational efficiency of URANS. Finally, turbulent flows over complex terrain in coastal areas are investigated by URANS and validated by wind tunnel tests. The predicted mean and standard deviation of streamwise velocity over complex terrain by URANS are in good agreement with the experimental data, while those by RANS are overestimated or underestimated.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 105991"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2024.105996
Yuang Wu , Shuo Liu , Jiachen Huang
Real-time forecasting of wind fields is an essential prerequisite for computational fluid predictions of pollutant transport. In the domain of data assimilation for real-time weather forecasting, obtaining high-quality meteorological data measurements poses a challenge that significantly impacts prediction accuracy. Predicting wind direction through data assimilation presents an inverse problem, and low-quality wind direction data resulting from suboptimal sensor placement can lead to ill-posedness when constructing proxy models. Consequently, previous research has extensively investigated the optimal placement of meteorological sensors. However, the data assimilation experiment has thus introduced uncertainties associated with the positions of the sensors. To achieve this goal, this study proposes a adaptive data assimilation model. This model introduces the concept of local convergence intervals on reduced-order response model, and deconstructs ill-posed intervals into well-posed intervals, and obtains a unique solution interval by regularization through the convergence range distance fusing. Finally, the model selects sensors using adaptive local weights, and implements the data assimilation process using inverse Ensemble Kalman Filter. This paper employs data from the Huailai Test Station to design simulated wind direction experiments.The results indicate that the method is capable of overcoming the shortcomings of sensor placement and can enhance the accuracy of prediction.
{"title":"A multi-sensor interval fusion adaptive regularization data assimilation model for wind direction prediction","authors":"Yuang Wu , Shuo Liu , Jiachen Huang","doi":"10.1016/j.jweia.2024.105996","DOIUrl":"10.1016/j.jweia.2024.105996","url":null,"abstract":"<div><div>Real-time forecasting of wind fields is an essential prerequisite for computational fluid predictions of pollutant transport. In the domain of data assimilation for real-time weather forecasting, obtaining high-quality meteorological data measurements poses a challenge that significantly impacts prediction accuracy. Predicting wind direction through data assimilation presents an inverse problem, and low-quality wind direction data resulting from suboptimal sensor placement can lead to ill-posedness when constructing proxy models. Consequently, previous research has extensively investigated the optimal placement of meteorological sensors. However, the data assimilation experiment has thus introduced uncertainties associated with the positions of the sensors. To achieve this goal, this study proposes a adaptive data assimilation model. This model introduces the concept of local convergence intervals on reduced-order response model, and deconstructs ill-posed intervals into well-posed intervals, and obtains a unique solution interval by regularization through the convergence range distance fusing. Finally, the model selects sensors using adaptive local weights, and implements the data assimilation process using inverse Ensemble Kalman Filter. This paper employs data from the Huailai Test Station to design simulated wind direction experiments.The results indicate that the method is capable of overcoming the shortcomings of sensor placement and can enhance the accuracy of prediction.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 105996"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2025.106005
Oddbjørn Kildal, Øyvind Wiig Petersen, Ole Øiseth
The present study investigates the effect of turbulence on aerodynamic derivatives (ADs) and the uncertainty of AD estimates due to buffeting forces. Wind tunnel experiments were conducted, using forced vibration testing to analyze changes in estimated ADs with increasing turbulence intensity. The experimental results revealed a significant scatter in the AD estimates, indicating the stochastic influence of buffeting forces on the estimation of ADs. Monte Carlo (MC) simulations were performed to further investigate this phenomenon. The MC simulations demonstrated that larger buffeting forces lead to larger uncertainty in estimated ADs, and highlighted the challenge of accurate estimation in the presence of turbulent flow. Despite challenges with the system identification, the study indicated that changes in aerodynamic damping due to turbulence are likely. In addition, closed-form analytical expressions for uncertainty estimation in ADs due to noise yielded uncertainty estimates that corresponded well with the experiments and the MC simulations. It was shown that the uncertainty of estimated ADs in turbulent flow can be decreased by increasing measurement duration and increasing the forced motion amplitude.
{"title":"On the uncertainty of aerodynamic derivatives obtained using forced vibration tests in active grid generated turbulent flow","authors":"Oddbjørn Kildal, Øyvind Wiig Petersen, Ole Øiseth","doi":"10.1016/j.jweia.2025.106005","DOIUrl":"10.1016/j.jweia.2025.106005","url":null,"abstract":"<div><div>The present study investigates the effect of turbulence on aerodynamic derivatives (ADs) and the uncertainty of AD estimates due to buffeting forces. Wind tunnel experiments were conducted, using forced vibration testing to analyze changes in estimated ADs with increasing turbulence intensity. The experimental results revealed a significant scatter in the AD estimates, indicating the stochastic influence of buffeting forces on the estimation of ADs. Monte Carlo (MC) simulations were performed to further investigate this phenomenon. The MC simulations demonstrated that larger buffeting forces lead to larger uncertainty in estimated ADs, and highlighted the challenge of accurate estimation in the presence of turbulent flow. Despite challenges with the system identification, the study indicated that changes in aerodynamic damping due to turbulence are likely. In addition, closed-form analytical expressions for uncertainty estimation in ADs due to noise yielded uncertainty estimates that corresponded well with the experiments and the MC simulations. It was shown that the uncertainty of estimated ADs in turbulent flow can be decreased by increasing measurement duration and increasing the forced motion amplitude.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 106005"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2024.105971
Terigen Bao , Zhengnong Li , Ou Pu , Ying Yang , Bin Huang , Honghua Wu
This paper investigates the wind interference effect on the rear row of photovoltaic modules as wind passes through the front row in a multi-row tracking photovoltaic array. Through field wind pressure measurements, we comprehensively evaluated the wind pressure interference effect under various tilt angle and wind direction angles, including variations in the wind pressure coefficient, wind force coefficient, central axis torque coefficient, column base moment coefficient, and fluctuating wind pressure power spectrum. The results indicate that when the wind direction angle is perpendicular to the panel width (L), the interference effect on the rear row is more significant, observed as a shading effect on the rear wind pressure coefficient, wind force coefficient, central axis torque coefficient, and column base moment coefficient. The interference effect gradually weakens as the wind direction angle increases/decreases; in the small tilt angle range (0° < β < 15°), the interference effect on the rear row is minimal. Additionally, under high tilt angle conditions, the third row experienced relatively higher wind forces compared to the second row. The interference effect of the fluctuating wind pressure power spectrum primarily manifests in the variation of vortex shedding frequency, significantly affecting the frequency peak of the rear components in the high-frequency band. The sensitivity of vortex shedding to wind direction and tilt angle adds complexity to the wind-resistant design of tracked PV arrays. This study offers valuable insights for designing tracking photovoltaic arrays to withstand wind forces.
{"title":"Field measurement-based research on wind pressure interference effects of tracking photovoltaic arrays","authors":"Terigen Bao , Zhengnong Li , Ou Pu , Ying Yang , Bin Huang , Honghua Wu","doi":"10.1016/j.jweia.2024.105971","DOIUrl":"10.1016/j.jweia.2024.105971","url":null,"abstract":"<div><div>This paper investigates the wind interference effect on the rear row of photovoltaic modules as wind passes through the front row in a multi-row tracking photovoltaic array. Through field wind pressure measurements, we comprehensively evaluated the wind pressure interference effect under various tilt angle and wind direction angles, including variations in the wind pressure coefficient, wind force coefficient, central axis torque coefficient, column base moment coefficient, and fluctuating wind pressure power spectrum. The results indicate that when the wind direction angle is perpendicular to the panel width (L), the interference effect on the rear row is more significant, observed as a shading effect on the rear wind pressure coefficient, wind force coefficient, central axis torque coefficient, and column base moment coefficient. The interference effect gradually weakens as the wind direction angle increases/decreases; in the small tilt angle range (0° < <em>β</em> < 15°), the interference effect on the rear row is minimal. Additionally, under high tilt angle conditions, the third row experienced relatively higher wind forces compared to the second row. The interference effect of the fluctuating wind pressure power spectrum primarily manifests in the variation of vortex shedding frequency, significantly affecting the frequency peak of the rear components in the high-frequency band. The sensitivity of vortex shedding to wind direction and tilt angle adds complexity to the wind-resistant design of tracked PV arrays. This study offers valuable insights for designing tracking photovoltaic arrays to withstand wind forces.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 105971"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2024.106001
Wei Wang , Yishuai Gao , Naoki Ikegaya
Wind speed probability distribution functions (PDFs) are crucial for evaluating urban wind environments. While previous studies have used unimodal distribution functions to model PDFs, bimodal patterns are also observed in urban areas. To more accurately model unimodal and bimodal PDFs, this study assessed the applicability of the mixture Weibull distribution (2W2W). The performance of the two-parameter Weibull distribution (2W) was also analyzed for comparison. Three parameter estimation methods (method of moments (MM), method of L-moments (LM), and maximum likelihood method (ML)) were applied to wind speed data of an isolated building case from a LES database. It was found that L-moments show non-linear relationships with moments, but with smaller magnitudes. 2W2W outperforms 2W in estimating both moments and L-moments, especially for higher-order statistics. 2W2W has the potential to better capture both unimodal and bimodal distributions compared to 2W. While 2W2W generally outperforms 2W under MM, noticeable oscillations were observed at some points. Although ML is the most accurate method at most points, LM still outperforms ML at specific locations based on both 2W and 2W2W. This study is expected to offer valuable insights into modeling PDFs for urban wind environments.
{"title":"Approximating wind speed probability distributions around a building by mixture weibull distribution with the methods of moments and L-moments","authors":"Wei Wang , Yishuai Gao , Naoki Ikegaya","doi":"10.1016/j.jweia.2024.106001","DOIUrl":"10.1016/j.jweia.2024.106001","url":null,"abstract":"<div><div>Wind speed probability distribution functions (PDFs) are crucial for evaluating urban wind environments. While previous studies have used unimodal distribution functions to model PDFs, bimodal patterns are also observed in urban areas. To more accurately model unimodal and bimodal PDFs, this study assessed the applicability of the mixture Weibull distribution (2W2W). The performance of the two-parameter Weibull distribution (2W) was also analyzed for comparison. Three parameter estimation methods (method of moments (MM), method of L-moments (LM), and maximum likelihood method (ML)) were applied to wind speed data of an isolated building case from a LES database. It was found that L-moments show non-linear relationships with moments, but with smaller magnitudes. 2W2W outperforms 2W in estimating both moments and L-moments, especially for higher-order statistics. 2W2W has the potential to better capture both unimodal and bimodal distributions compared to 2W. While 2W2W generally outperforms 2W under MM, noticeable oscillations were observed at some points. Although ML is the most accurate method at most points, LM still outperforms ML at specific locations based on both 2W and 2W2W. This study is expected to offer valuable insights into modeling PDFs for urban wind environments.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 106001"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2025.106006
Bahareh Dokhaei , Khalid Abdelaziz , Behrouz Shafei , Partha Sarkar , Jared Hobeck , Alice Alipour
With the continuous emergence of high-rise structures globally, there is a growing concern regarding the impact of wind on these wind-sensitive buildings. Consequently, the objective of this study is to examine the performance of a large-scale aeroelastic model of a high-rise building by conducting wind tunnel tests at a geometric scale of 1:76. Furthermore, the effects of upstream interference and transient wind speed were studied to represent the real turbulent wind regime in urban landscapes. The results are reported in both time-domain and frequency-domain to reveal the response characteristics. A comprehensive study of the large-aeroelastic responses in terms of rms of accelerations, power spectral density, base shear forces, and base moment were investigated. The results demonstrated that the across-wind responses were higher than along-wind responses in all the situation of wind speed and directions. Also, the presence of the upstream building significantly amplifies the across-wind and torsional response of the aeroelastic model but has only a minor effect on the model's along-wind response. The study's results can be used to evaluate numerical simulation for calculating a tall building's wind-induced vibration, as well as finally be utilized to produce guidelines for minimizing wind-related damage and occupant discomfort caused by high vibration.
{"title":"Aeroelastic boundary layer tests of a 1:76 model of tall building and effects of adjacent building interference","authors":"Bahareh Dokhaei , Khalid Abdelaziz , Behrouz Shafei , Partha Sarkar , Jared Hobeck , Alice Alipour","doi":"10.1016/j.jweia.2025.106006","DOIUrl":"10.1016/j.jweia.2025.106006","url":null,"abstract":"<div><div>With the continuous emergence of high-rise structures globally, there is a growing concern regarding the impact of wind on these wind-sensitive buildings. Consequently, the objective of this study is to examine the performance of a large-scale aeroelastic model of a high-rise building by conducting wind tunnel tests at a geometric scale of 1:76. Furthermore, the effects of upstream interference and transient wind speed were studied to represent the real turbulent wind regime in urban landscapes. The results are reported in both time-domain and frequency-domain to reveal the response characteristics. A comprehensive study of the large-aeroelastic responses in terms of rms of accelerations, power spectral density, base shear forces, and base moment were investigated. The results demonstrated that the across-wind responses were higher than along-wind responses in all the situation of wind speed and directions. Also, the presence of the upstream building significantly amplifies the across-wind and torsional response of the aeroelastic model but has only a minor effect on the model's along-wind response. The study's results can be used to evaluate numerical simulation for calculating a tall building's wind-induced vibration, as well as finally be utilized to produce guidelines for minimizing wind-related damage and occupant discomfort caused by high vibration.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 106006"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143102834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wind tunnel experiments were performed to collect surface pressure data on twin staggered cylinders with longitudinal pitch ratios (L/D) of 2.4–7.7 and transverse pitch ratios (T/D) of −4 to 0 at Re = 4 × 104. Simultaneous measurements of the pressure and velocity fields were performed for typical flows. Seven distinct flow configurations were identified and classified, including a newly discovered one termed the shear layer low-frequency swinging (SLS) flow configuration. This configuration arises from the periodic swinging of the inner shear layer of the downstream cylinder, alternating between vertical and horizontal orientations with respect to the flow direction at a Strouhal number of 0.03. The surface pressure properties of the downstream cylinder are analyzed by investigating the vortex formation and evolution. Various vortex evolution processes have been discussed, including periodic and persistent reattachment, incident vortex collisions, gap-vortex pairing and rushing, high-frequency vortex merging, and high-frequency modulation. The high-frequency modulation interrupts the shedding of low-frequency vortices from the outer side of the downstream cylinder, leading to the intermittent formation of two vortices during one low-frequency period. Except for the twin street flow configuration, each shear layer of the downstream cylinder sheds vortices at different rates in the two-frequency case.
{"title":"Flow configuration improvement and vortex evolution of staggered cylinders","authors":"Yan-Jiao Guo , Xiang-Wei Min , Xi-Zhe Cheng , Wen-Li Chen","doi":"10.1016/j.jweia.2025.106012","DOIUrl":"10.1016/j.jweia.2025.106012","url":null,"abstract":"<div><div>Wind tunnel experiments were performed to collect surface pressure data on twin staggered cylinders with longitudinal pitch ratios (<em>L</em>/<em>D</em>) of 2.4–7.7 and transverse pitch ratios (<em>T</em>/<em>D</em>) of −4 to 0 at Re = 4 × 10<sup>4</sup>. Simultaneous measurements of the pressure and velocity fields were performed for typical flows. Seven distinct flow configurations were identified and classified, including a newly discovered one termed the shear layer low-frequency swinging (SLS) flow configuration. This configuration arises from the periodic swinging of the inner shear layer of the downstream cylinder, alternating between vertical and horizontal orientations with respect to the flow direction at a Strouhal number of 0.03. The surface pressure properties of the downstream cylinder are analyzed by investigating the vortex formation and evolution. Various vortex evolution processes have been discussed, including periodic and persistent reattachment, incident vortex collisions, gap-vortex pairing and rushing, high-frequency vortex merging, and high-frequency modulation. The high-frequency modulation interrupts the shedding of low-frequency vortices from the outer side of the downstream cylinder, leading to the intermittent formation of two vortices during one low-frequency period. Except for the twin street flow configuration, each shear layer of the downstream cylinder sheds vortices at different rates in the two-frequency case.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"257 ","pages":"Article 106012"},"PeriodicalIF":4.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143102838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jweia.2025.106008
Geng Tian , Dingyang Geng , Liangzhu (Leon) Wang , Theodore (Ted) Stathopoulos , Minping Wan , Shiyi Chen
Analytical urban canopy models (UCMs) based on Prandtl’s mixing length theory usually ignore the blockage effects caused by building structures, which greatly reduces their accuracy in representing wind flow and turbulence variations within urban boundary layers. This study employs large-eddy simulations under neutral atmospheric stratification to investigate the effects of various blockage ratios on wind dynamics in urban environments. Detailed analyses are conducted on variations in instantaneous flow fields, mean velocity, Reynolds shear stress, and vorticity around buildings. Results indicate that higher blockage ratios restrict airflow above buildings, leading to increased local wind speeds and intensified turbulence within the urban canopy layer. In contrast, lower blockage ratios allow smoother airflow over the canopy, minimizing interactions between the airflow and buildings. Vorticity analysis suggests that higher blockage ratios induce smaller, denser vortices in the wake region, while lower blockage ratios generate longer, more dispersed vortices near the rooftop. Furthermore, this study introduces a modified friction velocity that reduces the bias in velocity by about 17% at a low blockage ratio of 4.44%, resulting in a more accurate representation of the velocity distribution around buildings. As a result, for neutral stratification at a specific moment, known parameters such as atmospheric boundary layer height can be used to predict velocity without additional simulations, thus significantly reducing the computational costs.
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