Pub Date : 2024-10-13DOI: 10.1016/j.jweia.2024.105922
Tiantian Li , Xiaodong Zhang , Shengming Tang , Hongya Qu , Yuhua Yang , Li Li , Yongping Li
Accurate simulations of typhoon-induced wind speeds on wind farms are crucial for the refined assessment of typhoon risks in wind turbines. Southeastern coastal area in China is rich in wind resources but is also severely threatened by typhoons. As an extremely destructive weather system with complex structures, the refined near-surface wind fields of typhoons are difficult to simulate by meso-scale models for risk assessment. Therefore, a coupled meso- and micro-scale model under typhoon conditions is proposed to simulate typhoon-induced winds on a wind farm. The Coriolis force is considered in the coupled model to reflect the rotating effect of typhoons caused by the vortex structure. A coupling algorithm based on objective analysis is proposed to construct boundary conditions at the coupling interface, to consider the variation of inflow variables in the vertical and cross-wind directions. Model constants of the two-equation turbulence model are calibrated based on typhoon field observations, to more reasonably simulate typhoons. A validation study is conducted, and the results show that the maximum wind speed on the wind farm simulated by the coupled model exhibits an increased accuracy compared with that of the meso-scale model, where the absolute error decreases by 34%.
{"title":"A meso- to micro-scale coupled model under typhoon conditions considering vortex structure and coriolis effect for wind farms","authors":"Tiantian Li , Xiaodong Zhang , Shengming Tang , Hongya Qu , Yuhua Yang , Li Li , Yongping Li","doi":"10.1016/j.jweia.2024.105922","DOIUrl":"10.1016/j.jweia.2024.105922","url":null,"abstract":"<div><div>Accurate simulations of typhoon-induced wind speeds on wind farms are crucial for the refined assessment of typhoon risks in wind turbines. Southeastern coastal area in China is rich in wind resources but is also severely threatened by typhoons. As an extremely destructive weather system with complex structures, the refined near-surface wind fields of typhoons are difficult to simulate by meso-scale models for risk assessment. Therefore, a coupled meso- and micro-scale model under typhoon conditions is proposed to simulate typhoon-induced winds on a wind farm. The Coriolis force is considered in the coupled model to reflect the rotating effect of typhoons caused by the vortex structure. A coupling algorithm based on objective analysis is proposed to construct boundary conditions at the coupling interface, to consider the variation of inflow variables in the vertical and cross-wind directions. Model constants of the two-equation turbulence model are calibrated based on typhoon field observations, to more reasonably simulate typhoons. A validation study is conducted, and the results show that the maximum wind speed on the wind farm simulated by the coupled model exhibits an increased accuracy compared with that of the meso-scale model, where the absolute error decreases by 34%.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105922"},"PeriodicalIF":4.2,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434122","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 : 2024-10-13DOI: 10.1016/j.jweia.2024.105915
Jiajun Tan , Ping Tan , Jiurong Wu , Demin Feng
Seismically isolated buildings (SIBs) are built higher and higher for which wind-induced effect is of worldwide concern. To comprehensively study this effect, this paper proposes a theoretical framework of wind-induced fragility evaluation for SIBs. A Chinese seismically isolated high-rise engineering building is systematically evaluated as a case study. The probability wind load demand model for SIBs is developed. The wind-induced performance evaluation indices set according to different national codes are assessed and compared from a probabilistic perspective. A parametric analysis is conducted to explore a reasonable range of values for wind load partial factor. The cumulative fatigue damage at seismic isolation interface (SII) under extreme wind loads is investigated. Results show that SIB can generally meet performance requirements for lateral stiffness. The performance evaluation indices under 1-year return period wind load are more demanding than those under 10-year return period wind load. The value of wind load partial factor is recommended to be within the range of 1.4–1.6 for sufficient wind-resistance stability without compromising seismic reduction performance. The LRB used in SII not only provides wind-resistance stability, but also perform well in resisting wind-induced fatigue damage. Nevertheless, periodic inspections are necessary to assess wind-induced residual deformation at SII.
{"title":"Evaluation of wind-induced fragility and cumulative fatigue damage on seismically isolated high-rise building","authors":"Jiajun Tan , Ping Tan , Jiurong Wu , Demin Feng","doi":"10.1016/j.jweia.2024.105915","DOIUrl":"10.1016/j.jweia.2024.105915","url":null,"abstract":"<div><div>Seismically isolated buildings (SIBs) are built higher and higher for which wind-induced effect is of worldwide concern. To comprehensively study this effect, this paper proposes a theoretical framework of wind-induced fragility evaluation for SIBs. A Chinese seismically isolated high-rise engineering building is systematically evaluated as a case study. The probability wind load demand model for SIBs is developed. The wind-induced performance evaluation indices set according to different national codes are assessed and compared from a probabilistic perspective. A parametric analysis is conducted to explore a reasonable range of values for wind load partial factor. The cumulative fatigue damage at seismic isolation interface (SII) under extreme wind loads is investigated. Results show that SIB can generally meet performance requirements for lateral stiffness. The performance evaluation indices under 1-year return period wind load are more demanding than those under 10-year return period wind load. The value of wind load partial factor is recommended to be within the range of 1.4–1.6 for sufficient wind-resistance stability without compromising seismic reduction performance. The LRB used in SII not only provides wind-resistance stability, but also perform well in resisting wind-induced fatigue damage. Nevertheless, periodic inspections are necessary to assess wind-induced residual deformation at SII.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105915"},"PeriodicalIF":4.2,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433395","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 : 2024-10-12DOI: 10.1016/j.jweia.2024.105913
Terigen Bao , Zhengnong Li , Ou Pu , Bin Huang
This study presents a novel investigation into the impact of non-Gaussian characteristics on wind pressure peak factors and extreme values in photovoltaic structural panels, addressing a critical gap in current design methodologies. A wind tunnel test was conducted on a rigid model of an adjustable-tilt solar photovoltaic system, providing essential panel wind pressure data. Through a comprehensive analysis of wind pressure time history, probability density, skewness, kurtosis, and statistical distributions, this research identified distinct non-Gaussian characteristics and highlighted sensitive areas on the panel. The study utilized three extreme value estimation methods to calculate peak wind pressures and compared their accuracy. Results demonstrate that the GPD method offers the most precise calculations of extreme wind pressure, outperforming traditional Gaussian-based approaches, which often underestimate peak pressures by 30%–50%. Additionally, the comparison of full-direction wind data with single wind direction extremes reveals potential overestimations in design values, suggesting that using one-directional extremes could inflate extreme wind pressure by 1.1–1.25 times for positive and 1.1 to 1.15 times for negative values. This study underscores the necessity of incorporating non-Gaussian features and full-direction wind considerations in the structural design of photovoltaic systems to avoid underestimation or over-design, particularly in sensitive regions. These findings contribute valuable insights for enhancing the precision and safety of structural design in renewable energy applications.
{"title":"Research on probabilistic characteristics and wind pressure extreme values of adjustable-tilt solar photovoltaic systems panels under full-direction wind","authors":"Terigen Bao , Zhengnong Li , Ou Pu , Bin Huang","doi":"10.1016/j.jweia.2024.105913","DOIUrl":"10.1016/j.jweia.2024.105913","url":null,"abstract":"<div><div>This study presents a novel investigation into the impact of non-Gaussian characteristics on wind pressure peak factors and extreme values in photovoltaic structural panels, addressing a critical gap in current design methodologies. A wind tunnel test was conducted on a rigid model of an adjustable-tilt solar photovoltaic system, providing essential panel wind pressure data. Through a comprehensive analysis of wind pressure time history, probability density, skewness, kurtosis, and statistical distributions, this research identified distinct non-Gaussian characteristics and highlighted sensitive areas on the panel. The study utilized three extreme value estimation methods to calculate peak wind pressures and compared their accuracy. Results demonstrate that the GPD method offers the most precise calculations of extreme wind pressure, outperforming traditional Gaussian-based approaches, which often underestimate peak pressures by 30%–50%. Additionally, the comparison of full-direction wind data with single wind direction extremes reveals potential overestimations in design values, suggesting that using one-directional extremes could inflate extreme wind pressure by 1.1–1.25 times for positive and 1.1 to 1.15 times for negative values. This study underscores the necessity of incorporating non-Gaussian features and full-direction wind considerations in the structural design of photovoltaic systems to avoid underestimation or over-design, particularly in sensitive regions. These findings contribute valuable insights for enhancing the precision and safety of structural design in renewable energy applications.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105913"},"PeriodicalIF":4.2,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420054","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}
This study explores the role of Reynolds numbers (Re) in wake-induced vibrations (WIVs) of two cylinders, specifically wake galloping and two-degree-of-freedom coupled flutter on the downstream cylinder. The center-to-center distances between the cylinders were 3.0D −5.0D in along-flow direction and 0.0D −2.0D in cross-flow direction (D is the diameter of the cylinders). The Re ranged from 1.4 × 104–6.7 × 104, within the subcritical Re regime of a smooth cylinder. The supercritical Re regime was realized by winding 12 spiral protuberances along the cylinders to lower the critical Re. Descriptions of wake interference of two smooth cylinders at Re = 850–6.5 × 105 were summarized from the literature. Wake interference strongly depended on Re, even within the subcritical Re regime. WIVs mostly occurred in the upper subcritical Re regime with strong wake interference. In the supercritical Re regime, the wakes of the cylinders were narrowed and vortex shedding was suppressed. Consequently, the wake interference and WIVs were weakened or completely disappeared. The cylinders fitted with 12 spiral protuberances reportedly reached the supercritical Re regime at Re = 3.1 × 104. Resultantly, they were stable against WIVs above this Re even at close spacing, and suitable for stay cable applications.
本研究探讨了雷诺数（Re）在两个气缸的尾流诱导振动（WIVs）中的作用，特别是下游气缸上的尾流奔腾和两自由度耦合扑腾。圆筒之间的中心到中心距离在顺流方向为 3.0D -5.0D，在横流方向为 0.0D -2.0D（D 为圆筒直径）。Re 值范围为 1.4 × 104-6.7 × 104，属于光滑圆柱体的亚临界 Re 值范围。通过沿圆柱体缠绕 12 个螺旋突起来降低临界 Re 值，从而实现了超临界 Re 值。从文献中总结了两个光滑圆柱体在 Re = 850-6.5 × 105 条件下的唤醒干扰。即使在亚临界 Re 条件下，唤醒干涉也与 Re 密切相关。WIVs 主要发生在具有强烈唤醒干涉的亚临界 Re 上层。在超临界 Re 状态下，圆柱体的湍流变窄，涡流脱落受到抑制。因此，唤醒干扰和 WIV 被减弱或完全消失。据报道，装有 12 个螺旋突起的圆筒在 Re = 3.1 × 104 时达到了超临界 Re 状态。因此，即使在间距很近的情况下，它们也能稳定地抵御高于此 Re 值的 WIV，适用于留缆应用。
{"title":"Effects of Reynolds number and surface modification on wake-induced vibrations of two staggered circular cylinders","authors":"Thu Dao, Hisato Matsumiya, Kyohei Noguchi, Gabriel Mohallem, Runze Xu, Tomomi Yagi","doi":"10.1016/j.jweia.2024.105912","DOIUrl":"10.1016/j.jweia.2024.105912","url":null,"abstract":"<div><div>This study explores the role of Reynolds numbers (<em>Re</em>) in wake-induced vibrations (WIVs) of two cylinders, specifically wake galloping and two-degree-of-freedom coupled flutter on the downstream cylinder. The center-to-center distances between the cylinders were 3.0<em>D</em> −5.0<em>D</em> in along-flow direction and 0.0<em>D</em> −2.0<em>D</em> in cross-flow direction (<em>D</em> is the diameter of the cylinders). The <em>Re</em> ranged from 1.4 × 10<sup>4</sup>–6.7 × 10<sup>4</sup>, within the subcritical <em>Re</em> regime of a smooth cylinder. The supercritical <em>Re</em> regime was realized by winding 12 spiral protuberances along the cylinders to lower the critical <em>Re</em>. Descriptions of wake interference of two smooth cylinders at <em>Re</em> = 850–6.5 × 10<sup>5</sup> were summarized from the literature. Wake interference strongly depended on <em>Re</em>, even within the subcritical <em>Re</em> regime. WIVs mostly occurred in the upper subcritical <em>Re</em> regime with strong wake interference. In the supercritical <em>Re</em> regime, the wakes of the cylinders were narrowed and vortex shedding was suppressed. Consequently, the wake interference and WIVs were weakened or completely disappeared. The cylinders fitted with 12 spiral protuberances reportedly reached the supercritical <em>Re</em> regime at <em>Re</em> = 3.1 × 10<sup>4</sup>. Resultantly, they were stable against WIVs above this <em>Re</em> even at close spacing, and suitable for stay cable applications.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105912"},"PeriodicalIF":4.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420053","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 : 2024-10-07DOI: 10.1016/j.jweia.2024.105909
Biao Tong , Yang Liang , Jie Song , Gang Hu , Ahsan Kareem
The spatio-temporal variation of the wind pressure field is crucial for understanding structural loads and their effect on design. However, obtaining long-duration wind pressure time series around bluff bodies through wind tunnel tests or stochastic and computational simulations is both costly and time-consuming. To address this challenge, this study develops a deep learning (DL) model called WPTSE-Net for extending non-Gaussian wind pressure time series, thereby eliminating the need for the characterization of their nonlinear features and providing an end-to-end flexible framework for extending pressure coefficient time series. The key innovation of WPTSE-Net lies in the reconstruction of the encoder, utilizing prior knowledge to eliminate complex steps in searching for the latent space. This improvement not only enhances computational efficiency and model performance but also substantially reduces the amount of training data that is required for the DL generative model. Comparative results indicate that the proposed WPTSE-Net model outperforms traditional methods in terms of statistical characteristics, i.e., spectra, and peak value distributions. Thus, WPTSE-Net is highly suitable for practical engineering applications as it provides an efficient means of generating long-time series of wind pressure on bluff bodies in wind resistance design.
{"title":"Deep learning-based extension of wind pressure time series","authors":"Biao Tong , Yang Liang , Jie Song , Gang Hu , Ahsan Kareem","doi":"10.1016/j.jweia.2024.105909","DOIUrl":"10.1016/j.jweia.2024.105909","url":null,"abstract":"<div><div>The spatio-temporal variation of the wind pressure field is crucial for understanding structural loads and their effect on design. However, obtaining long-duration wind pressure time series around bluff bodies through wind tunnel tests or stochastic and computational simulations is both costly and time-consuming. To address this challenge, this study develops a deep learning (DL) model called WPTSE-Net for extending non-Gaussian wind pressure time series, thereby eliminating the need for the characterization of their nonlinear features and providing an end-to-end flexible framework for extending pressure coefficient time series. The key innovation of WPTSE-Net lies in the reconstruction of the encoder, utilizing prior knowledge to eliminate complex steps in searching for the latent space. This improvement not only enhances computational efficiency and model performance but also substantially reduces the amount of training data that is required for the DL generative model. Comparative results indicate that the proposed WPTSE-Net model outperforms traditional methods in terms of statistical characteristics, i.e., spectra, and peak value distributions. Thus, WPTSE-Net is highly suitable for practical engineering applications as it provides an efficient means of generating long-time series of wind pressure on bluff bodies in wind resistance design.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105909"},"PeriodicalIF":4.2,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420052","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 : 2024-10-05DOI: 10.1016/j.jweia.2024.105911
Mingyang Liu , Chen Jiang , Jin Yi , Guangjun Gao , Zan Deng , Huifen Zhu
The massive heat dissipation demands of the brake system in high-speed trains pose a significant obstacle to achieving higher operation speeds. Phase change material has attracted considerable attention in various fields due to their exceptional heat dissipation capabilities, yet their utilization in the brake system of high-speed trains remains unexplored. This study aims to investigate the feasibility of phase change material application in the brake system of high-speed train. Specifically, in Case A, the introduction of phase change material resulted in a notable 21% decrease in the average temperature and a remarkable 40% reduction in the maximum temperature difference within the brake system. The latent heat of the phase change material plays a crucial role in maintaining a substantial temperature differential between the cooling components and discs, thereby enhancing heat flux in the brake system. Phase change materials exhibit superior cooling performance compared to traditional air cooling methods in the brake system. To expedite the cooling process of phase change material and facilitate its transition from liquid to solid, an optimized brake system structure utilizing phase change material was proposed. This optimized design holds promise in enhancing the overall heat dissipation efficiency of the high-speed train brake system.
高速列车制动系统的巨大散热需求对实现更高的运行速度构成了重大障碍。相变材料因其优异的散热性能在各个领域都引起了广泛关注，但其在高速列车制动系统中的应用仍有待探索。本研究旨在探讨相变材料在高速列车制动系统中应用的可行性。具体而言，在案例 A 中，相变材料的引入使制动系统内的平均温度显著降低了 21%，最大温差显著降低了 40%。相变材料的潜热在维持冷却组件与制动盘之间的巨大温差方面发挥了关键作用，从而提高了制动系统中的热通量。与制动系统中传统的空气冷却方法相比，相变材料的冷却性能更为出色。为了加快相变材料的冷却过程并促进其从液态到固态的转变，我们提出了一种利用相变材料的优化制动系统结构。这种优化设计有望提高高速列车制动系统的整体散热效率。
{"title":"Numerical investigation on the heat dissipation of phase change materials used in the high-speed train brake system","authors":"Mingyang Liu , Chen Jiang , Jin Yi , Guangjun Gao , Zan Deng , Huifen Zhu","doi":"10.1016/j.jweia.2024.105911","DOIUrl":"10.1016/j.jweia.2024.105911","url":null,"abstract":"<div><div>The massive heat dissipation demands of the brake system in high-speed trains pose a significant obstacle to achieving higher operation speeds. Phase change material has attracted considerable attention in various fields due to their exceptional heat dissipation capabilities, yet their utilization in the brake system of high-speed trains remains unexplored. This study aims to investigate the feasibility of phase change material application in the brake system of high-speed train. Specifically, in Case A, the introduction of phase change material resulted in a notable 21% decrease in the average temperature and a remarkable 40% reduction in the maximum temperature difference within the brake system. The latent heat of the phase change material plays a crucial role in maintaining a substantial temperature differential between the cooling components and discs, thereby enhancing heat flux in the brake system. Phase change materials exhibit superior cooling performance compared to traditional air cooling methods in the brake system. To expedite the cooling process of phase change material and facilitate its transition from liquid to solid, an optimized brake system structure utilizing phase change material was proposed. This optimized design holds promise in enhancing the overall heat dissipation efficiency of the high-speed train brake system.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105911"},"PeriodicalIF":4.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420051","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 measurements have widely been used for validation of computational fluid dynamics simulations of natural ventilation airflows. However, the majority of such measurements employed simple generic single-zone buildings, while there is a lack of studies on realistic buildings including flow-critical geometrical features (e.g. internal partitions). To assess the effect of internal partitions at different incident flow angles (α = 0° and α = 30°), wind tunnel measurements of velocities in and around a cross-ventilated realistic residential building (with and without internal partition) were performed. Measurements were conducted at a geometric scale 1:40, using laser Doppler anemometry. Results indicate a large impact of the internal partition on indoor airflow distribution and resulting ventilation flow rates. For instance, for α = 0°, on the partitioned building side, regions of velocity increase (from ∼0 m/s to ∼80% of the outdoor reference velocity, Uref), but also regions of velocity decrease (from ∼50% of Uref to ∼0 m/s) were observed. The ventilation flow rate through the windows at the partitioned side decreased by 23% and 32%, respectively. For the partitioned building, a change from α = 0° to α = 30° resulted in regions of velocity increase from 0 m/s to ∼60% of Uref.
{"title":"Wind tunnel measurements of cross-ventilation flow in a realistic building geometry: Influence of building partitions and wind direction","authors":"Mutmainnah Sudirman , Stefanie Gillmeier , Twan van Hooff , Bert Blocken","doi":"10.1016/j.jweia.2024.105907","DOIUrl":"10.1016/j.jweia.2024.105907","url":null,"abstract":"<div><div>Wind tunnel measurements have widely been used for validation of computational fluid dynamics simulations of natural ventilation airflows. However, the majority of such measurements employed simple generic single-zone buildings, while there is a lack of studies on realistic buildings including flow-critical geometrical features (e.g. internal partitions). To assess the effect of internal partitions at different incident flow angles (α = 0° and α = 30°), wind tunnel measurements of velocities in and around a cross-ventilated realistic residential building (with and without internal partition) were performed. Measurements were conducted at a geometric scale 1:40, using laser Doppler anemometry. Results indicate a large impact of the internal partition on indoor airflow distribution and resulting ventilation flow rates. For instance, for α = 0°, on the partitioned building side, regions of velocity increase (from ∼0 m/s to ∼80% of the outdoor reference velocity, U<sub>ref</sub>), but also regions of velocity decrease (from ∼50% of U<sub>ref</sub> to ∼0 m/s) were observed. The ventilation flow rate through the windows at the partitioned side decreased by 23% and 32%, respectively. For the partitioned building, a change from α = 0° to α = 30° resulted in regions of velocity increase from 0 m/s to ∼60% of U<sub>ref</sub>.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105907"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419472","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 : 2024-10-04DOI: 10.1016/j.jweia.2024.105908
Minzhang Liu , Ni Gao , Zhiyu Song , Bin Yang , Xin Zhu , Jingwen Wu , Kaisen Liang
With the growing demand for efficient travel, tunnels are being lengthened and train speeds are being increased. High-speed subway brings new challenges to the flow environment of tunnel. Additionally, the emergence of express trains passing through stations without stopping has an enormous impact on the tunnel's and the station's flow field. This study focuses on a new type of station (NS) with overtaking and avoidance lines, allowing slow trains to stop for passengers to get on and off, while express trains pass through without stopping. The study analyzes pressure variation and wind speed when express trains pass through the NS without stopping. Different train speeds are taken into account. Based on this, the enhancement of station ventilation by utilizing the piston winds generated by express trains passing through NS is investigated. The air exchange effect and energy savings of the NS are explored. The results indicate that enhancing station air exchanges by fully utilizing piston wind saves about 190.68 kWh/day in mechanical ventilation energy consumption. This study contributes to the improvement of subway station construction and the advancement of subway train development. It can offer data assistance and theoretical direction for high-speed train operations.
{"title":"Numerical study on flow field of high-speed train passing through a new type of station","authors":"Minzhang Liu , Ni Gao , Zhiyu Song , Bin Yang , Xin Zhu , Jingwen Wu , Kaisen Liang","doi":"10.1016/j.jweia.2024.105908","DOIUrl":"10.1016/j.jweia.2024.105908","url":null,"abstract":"<div><div>With the growing demand for efficient travel, tunnels are being lengthened and train speeds are being increased. High-speed subway brings new challenges to the flow environment of tunnel. Additionally, the emergence of express trains passing through stations without stopping has an enormous impact on the tunnel's and the station's flow field. This study focuses on a new type of station (NS) with overtaking and avoidance lines, allowing slow trains to stop for passengers to get on and off, while express trains pass through without stopping. The study analyzes pressure variation and wind speed when express trains pass through the NS without stopping. Different train speeds are taken into account. Based on this, the enhancement of station ventilation by utilizing the piston winds generated by express trains passing through NS is investigated. The air exchange effect and energy savings of the NS are explored. The results indicate that enhancing station air exchanges by fully utilizing piston wind saves about 190.68 kWh/day in mechanical ventilation energy consumption. This study contributes to the improvement of subway station construction and the advancement of subway train development. It can offer data assistance and theoretical direction for high-speed train operations.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105908"},"PeriodicalIF":4.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419473","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 : 2024-10-02DOI: 10.1016/j.jweia.2024.105905
Li-ming Zhao , Wen-ming Zhang , Zhi-wei Wang , Yao-jun Ge , Nan Jiang
Machine learning-based aerodynamic reduced-order models (ROMs) combine high accuracy with extremely low computational costs, making them highly effective in predicting nonlinear and unsteady bridge aerodynamic forces. Although several machine learning-based nonlinear aerodynamic models have been developed, the majority are built on a single wind speed parameter. However, in nonlinear aerodynamic prediction and aeroelastic analysis of bridges, the variability in incoming wind speed significantly influences the computed results. A ROM relying solely on a single wind speed lacks the ability to accurately forecast the intricate dynamic behaviors arising from changes in wind speed. When the incoming wind speed changes, the model's prediction accuracy significantly decreases. Usually, it is necessary to establish a new database and train a new model, which not only increases time and cost but also greatly reduces the convenience of the ROM. Addressing this challenge, this study proposes a multiple-wind-speed (MWS) nonlinear unsteady bridge aerodynamic model based on the LSTM deep neural network. Taking the Taohuayu Yellow River Bridge in the Henan Province of China as an example, the modeling process of the proposed MWS-ROM is demonstrated, along with non-linear aerodynamic predictions of the deck under various conditions and aerodynamic-elastic analysis of the deck under different wind speeds. The research results show that the trained LSTM network can accurately predict the nonlinear aerodynamic forces of bridges under single and double degrees of freedom vibration conditions. The MWS-ROM performed well in predicting convergent vibrations at low wind speeds and limits cycle oscillations at high wind speeds, aligning closely with results from the CFD full-order model. Compared to CFD, the aerodynamic ROM based on the LSTM network significantly enhances computational efficiency, consequently boosting the convenience and efficiency of bridge flutter analysis. Additionally, the methodology proposed herein can be extended for wind-induced vibration control and response prediction in other types of deck sections.
基于机器学习的空气动力学降阶模型（ROM）兼具高精度和极低的计算成本，因此在预测非线性和非稳态桥梁空气动力方面非常有效。虽然已经开发了多个基于机器学习的非线性空气动力学模型，但大多数模型都是基于单一风速参数建立的。然而，在桥梁的非线性气动力预测和气动弹性分析中，风速的变化会对计算结果产生重大影响。仅依靠单一风速的 ROM 无法准确预测风速变化引起的复杂动态行为。当进入的风速发生变化时，模型的预测精度会明显降低。通常情况下，需要建立新的数据库并训练新的模型，这不仅增加了时间和成本，还大大降低了 ROM 的便利性。针对这一难题，本研究提出了一种基于 LSTM 深度神经网络的多风速（MWS）非线性非稳态桥梁空气动力学模型。以中国河南省桃花峪黄河大桥为例，演示了所提出的 MWS-ROM 的建模过程，以及不同条件下桥面的非线性气动预测和不同风速下桥面的气动弹性分析。研究结果表明，训练有素的 LSTM 网络可以准确预测单自由度和双自由度振动条件下桥梁的非线性空气动力。MWS-ROM 在预测低风速下的收敛振动和高风速下的极限周期振荡方面表现出色，与 CFD 全阶模型的结果非常接近。与 CFD 相比，基于 LSTM 网络的气动 ROM 显著提高了计算效率，从而提高了桥梁飘移分析的便利性和效率。此外，本文提出的方法还可扩展用于其他类型桥面截面的风致振动控制和响应预测。
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Pub Date : 2024-10-01DOI: 10.1016/j.jweia.2024.105906
Seika Tanji , Tetsuya Takemi , Guangdong Duan
This study examines turbulent airflow and upward heat transport in real urban environments using a building-resolving large-eddy simulation model to understand the characteristics of turbulent airflow and upward heat transport when geometrical distributions of buildings are modified. The target areas were two real urban districts within Osaka City, Japan, having different morphological features. In the numerical experiments, the initial condition was set to a neutral condition in which temperature is uniformly distributed vertically, and buildings emitted heat at a constant rate. The results in the two districts indicated that the features of turbulence and heat transport distinctly differed with different building arrangement. Specifically, taller buildings significantly decelerated airflows and induced warming behind buildings. More high-rise buildings (which resulted in a larger building variability) in a district with a larger building density caused a large heat flux and warming at higher levels. The sensitivity experiments in which a density and height variability of buildings were modified showed that a building density at higher levels and a building height variability significantly influenced warming at upper levels. An increased building height variability weakened wind speed and disturbed horizontal heat advection, whereas a large building density caused numerous heat sources.
{"title":"Impacts of building modifications on the turbulent flow and heat transfer in urban surface boundary layers","authors":"Seika Tanji , Tetsuya Takemi , Guangdong Duan","doi":"10.1016/j.jweia.2024.105906","DOIUrl":"10.1016/j.jweia.2024.105906","url":null,"abstract":"<div><div>This study examines turbulent airflow and upward heat transport in real urban environments using a building-resolving large-eddy simulation model to understand the characteristics of turbulent airflow and upward heat transport when geometrical distributions of buildings are modified. The target areas were two real urban districts within Osaka City, Japan, having different morphological features. In the numerical experiments, the initial condition was set to a neutral condition in which temperature is uniformly distributed vertically, and buildings emitted heat at a constant rate. The results in the two districts indicated that the features of turbulence and heat transport distinctly differed with different building arrangement. Specifically, taller buildings significantly decelerated airflows and induced warming behind buildings. More high-rise buildings (which resulted in a larger building variability) in a district with a larger building density caused a large heat flux and warming at higher levels. The sensitivity experiments in which a density and height variability of buildings were modified showed that a building density at higher levels and a building height variability significantly influenced warming at upper levels. An increased building height variability weakened wind speed and disturbed horizontal heat advection, whereas a large building density caused numerous heat sources.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105906"},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358828","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}
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