Journal of Wind Engineering and Industrial Aerodynamics最新文献

{"title":"Aerodynamic and codification study of low-rise buildings: Part II – Partially elevated structures","authors":"Haitham A. Ibrahim ,&nbsp;Amal Elawady ,&nbsp;David O. Prevatt","doi":"10.1016/j.jweia.2024.105925","DOIUrl":"10.1016/j.jweia.2024.105925","url":null,"abstract":"<div><div>This study constitutes part II of an extensive study where the aerodynamics of elevated buildings is investigated using large-scale wind tunnel testing. Part II focuses on the case of elevated buildings with partially enclosed spaces beneath the elevated floor. For this purpose, four 1:10 scaled models of elevated single-story gable-roof buildings were selected, three of which were partially elevated with enclosed regions covering areas ranging from 19% to 54% of the model footprint. The tests aimed to examine the effect of the enclosed regions below the floor on the distribution of the localized peak pressure coefficients on the walls, floor, and roof surfaces of the models. Furthermore, the study evaluates the ASCE 7–22 provisions and the proposed provisions, presented by the authors in Part I, for estimating external wind pressure coefficients acting on the floor, roof, and walls of elevated buildings. The results indicate that enclosed regions below the floor significantly alter the aerodynamics of elevated low-rise buildings and could increase the wind-induced loads on the roof and walls of such structures, with the increase in some cases exceeding 80%. Furthermore, the results align well with the proposed modifications by the authors in Part I to the ASCE 7 provisions for estimating the external pressure coefficients for the various zones of low-rise buildings, addressing the underestimation issues previously identified within the current ASCE standard.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"255 ","pages":"Article 105925"},"PeriodicalIF":4.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129610","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}

{"title":"Aerodynamic and codification study of low-rise buildings: Part I – Fully elevated structures","authors":"Haitham A. Ibrahim ,&nbsp;Amal Elawady ,&nbsp;David O. Prevatt","doi":"10.1016/j.jweia.2024.105924","DOIUrl":"10.1016/j.jweia.2024.105924","url":null,"abstract":"<div><div>Elevated residential buildings are widely used in cyclone- and hurricane-prone coastal regions, such as Australia and the United States, as an effective solution to mitigate both storm surge damage and the impacts of extreme winds. The recent edition of ASCE 7–22 introduced wind design provisions for elevated structures for the first time, but these provisions remain under ongoing refinement. This study aims to assess the adequacy of the current ASCE 7–22 wind pressure coefficient provisions for elevated structures by conducting large-scale boundary layer wind tunnel tests at FIU's Wall of Wind Facility. The tests explored the aerodynamics of elevated buildings with varying heights and aspect ratios. Eight 1:10 scale gable-roof buildings were constructed based on post-hurricane damage reports, and peak pressure coefficients (<span><math><mrow><msub><mrow><mi>G</mi><mi>C</mi></mrow><mi>p</mi></msub></mrow></math></span>) were estimated for the floor, roof, and walls. These values were compared against the existing ASCE 7–22 provisions, revealing a significant underestimation of the external pressure coefficients. Based on the results, this study proposes increasing the <span><math><mrow><msub><mrow><mi>G</mi><mi>C</mi></mrow><mi>p</mi></msub></mrow></math></span> boundaries of specific zones by 50%–127% and introduces two new floor zones for more accurate estimation of wind pressure coefficients on elevated buildings. These findings have broad implications for improving the wind performance of elevated structures, particularly in cyclone- and hurricane-prone regions globally. It is envisioned that the results of this study, along with those in the companion paper, will be considered by the ASCE 7 Subcommittee on Wind Loads for potential inclusion in the next edition of ASCE 7–28, contributing to more resilient building designs.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"255 ","pages":"Article 105924"},"PeriodicalIF":4.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129609","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}

{"title":"Turbulence and flapping pivot axis effects on torsional flutter harvester efficiency by closed-form formula","authors":"Yuhui Qin,&nbsp;Luca Caracoglia","doi":"10.1016/j.jweia.2024.105938","DOIUrl":"10.1016/j.jweia.2024.105938","url":null,"abstract":"<div><div>This “Short Communication” investigates the dynamics of a torsional-flutter energy harvester in atmospheric winds with stationary turbulence. This apparatus is an example of a flutter mill, which operates by exploiting aeroelastic instability as a competitive alternative and as a renewable energy supply for one or few housing units. The apparatus has a rigid blade-airfoil that rotates about a pivot to generate flapping motion. Contrary to recent studies by the second author, the effect of random stationary turbulence on flutter onset is examined by an analytical approach, employed by Scanlan (1997) for bridge flutter analysis. Turbulence effect is simulated by suitably modifying the span-wise coherence equation of the aeroelastic load. The incipient flutter threshold is found as a function of turbulence properties. Various configurations are studied, i.e., pivot position, aspect ratio, turbulence coherence decay parameter and structural damping. The objective is to perform a thorough sensitivity analysis as the necessary premise for the planned, future examination of post-critical instability and operational efficiency of the harvester by suitable modeling and wind tunnel tests.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105938"},"PeriodicalIF":4.2,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743783","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}

{"title":"Interpolating wind pressure time-histories around a tall building - A deep learning-based approach","authors":"D.P.P. Meddage ,&nbsp;D. Mohotti ,&nbsp;Kasun Wijesooriya ,&nbsp;C.K. Lee ,&nbsp;K.C.S. Kwok","doi":"10.1016/j.jweia.2024.105968","DOIUrl":"10.1016/j.jweia.2024.105968","url":null,"abstract":"<div><div>Machine learning research on estimating wind pressure on tall buildings has primarily focused on mean pressure predictions with limited studies on time history interpolations. In this study, a Deep Neural Network model (DNN) and Extreme Gradient Boost (XGB) were employed to interpolate the wind pressure time histories around the Commonwealth Aeronautical Advisory Research Council (CAARC) standard tall building for four wind directions. The results of a wind tunnel experiment conducted on a CAARC tall building model (1:300) were used to validate the Computational Fluid Dynamics (CFD) models. The pressure data extracted from the CFD model was used to train the DNN and XGB models. The results demonstrated that both XGB (R² = 93%) and DNN (R² = 96%) accurately modelled the wind pressure time histories around the CAARC building. Both models implicitly reconstructed flow features (e.g. pressure gradients, flow separation and conical vortex formations) on the building and compared well with the CFD results. Furthermore, the time-averaged pressure quantities obtained from machine learning models, and CFD models presented good agreement with wind tunnel results. The study shows that the DNN approach is a time-efficient and accurate complementary tool for interpolating wind pressure time histories on isolated tall buildings.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105968"},"PeriodicalIF":4.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719706","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}

{"title":"Wind loads on flat plates and porous screens installed on the track surface during the passage of high-speed trains","authors":"Yutaka Sakuma ,&nbsp;Takashi Nakano ,&nbsp;Tatsuya Inoue ,&nbsp;Youta Kakizaki","doi":"10.1016/j.jweia.2024.105951","DOIUrl":"10.1016/j.jweia.2024.105951","url":null,"abstract":"<div><div>Field measurements of wind pressure fluctuations during high-speed train passages were conducted by horizontally installing several flat plates above sleepers on a straight section of ballasted track. Wind pressure sensors were attached to the top and bottom surfaces of these plates to capture vertical wind pressure fluctuations. The primary objectives of this study are to investigate the nature of fluctuating wind pressure on flat plates during high-speed train passages, to estimate the wind loads acting on flat plates and porous screens on the track surface, and to evaluate their susceptibility to being lifted by wind loads. The results reveal that the differential pressure, which is the primary contributor to wind loads on the flat plates, is driven by the turbulent flow beneath the middle section of the train. Additionally, wind pressure data were used to estimate the wind loads (lift forces) acting on the flat plates and porous screens due to the turbulent flow, and to calculate the fixation loads required to prevent lifting.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105951"},"PeriodicalIF":4.2,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719707","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}

{"title":"Experimental study on wind-induced vibration and aerodynamic interference effects of flexible photovoltaics","authors":"Wenhan Yang ,&nbsp;Jiahao Dai ,&nbsp;Wenli Chen","doi":"10.1016/j.jweia.2024.105965","DOIUrl":"10.1016/j.jweia.2024.105965","url":null,"abstract":"<div><div>This study investigates the wind-induced vibrations (WIVs) of photovoltaic (PV) modules possessing unique characteristics such as lightweight construction, low frequency, and susceptibility to wind loads, in contrast to stationary PV systems installed on rooftops and ground surfaces. The complex interference effects within rows of flexible PV arrays were investigated under varying angles of wind attack (AOAs) and inter-row distances, specifically focusing on wind directions of 0° and 180°. A comparative analysis of the WIV of a single row was also conducted. The findings indicated that both single- and multi-row PV modules experience flutter instability as wind speeds increase, resulting in significant vibrations at wind directions of 0° and 180°. Vertical vortex-induced vibrations (VIVs) were observed in multi-row arrays at lower wind speeds prior to the onset of flutter instability, whereas no VIVs occurred in the single-row configuration. Within the three-row array, the middle row exhibited the most significant VIVs. An increase in AOA was found to correlate with elevated maximum VIV responses, wind speed, and vortex amplitude. Throughout various flutter instability scenarios, the third row consistently maintained stable. Notably, the critical wind speed for flutter was lower at a wind direction of 180°, and the VIV response was more pronounced compared to that observed at 0°.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105965"},"PeriodicalIF":4.2,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142707034","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}

{"title":"Calibration of pressures measured via tubing systems: Accounting for laboratory environmental variations between tubing response measurement and wind tunnel testing","authors":"DongHun Yeo ,&nbsp;Yong Chul Kim","doi":"10.1016/j.jweia.2024.105962","DOIUrl":"10.1016/j.jweia.2024.105962","url":null,"abstract":"<div><div>Accurate pressure measurements on structures via tubing systems during wind tunnel tests are crucial for precise estimation of wind loads. While calibration studies have traditionally focused on the contribution of tubing configuration to pressure distortion, they often overlook the effects of environmental parameter changes between the measurement of tubing response and aerodynamic pressure on structures. However, higher atmospheric pressure and lower ambient temperature can substantially increase tubing response distortion. To address this, this study introduces a dynamic calibration approach that accounts for such laboratory environmental changes. This method integrates the experimental transfer function, obtained under specific environmental conditions, with numerical estimates of the impact of environmental changes, to derive transfer functions for the desired environmental conditions. The effectiveness of this approach was validated using experimental and numerical transfer functions under two distinct environmental conditions. A case study for outdoor open-circuit laboratories revealed that neglecting environmental conditions during dynamic pressure calibrations could lead to overall average deviations in peak pressures across the channels on a building face of up to ≈ 5%, with local maximum deviations reaching ≈ 10%, respectively. Therefore, the proposed calibration method can significantly enhance the accuracy of pressure measurements via tubing systems, particularly when the tubing response and the pressures are measured under different environmental conditions.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105962"},"PeriodicalIF":4.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142707033","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}

{"title":"Alleviating tunnel aerodynamics through hybrid suction & blowing techniques applied to train nose sections","authors":"Wenhui Li ,&nbsp;Yifan Gu ,&nbsp;Weifeng Zhao ,&nbsp;Yelin Deng ,&nbsp;Xueliang Fan","doi":"10.1016/j.jweia.2024.105961","DOIUrl":"10.1016/j.jweia.2024.105961","url":null,"abstract":"<div><div>As high-speed railway lines upgrade speeds or develop ultra-high-speed trains, traditional passive measures may struggle to address tunnel aerodynamics and passenger comfort. This study employs numerical calculations to investigate the aerodynamic mitigation of an ultra-high-speed train traveling at <em>U</em> = 600 km/h through a tunnel, utilizing active suction &amp; blowing techniques in its streamlined nose sections. The simulation employs three-dimensional, compressible, unsteady Reynolds-averaged Navier-Stokes (URANS) methods, validated against full-scale experiments. The effects of slot shapes, suction directions, activation periods, and the suction &amp; blowing velocities (SB_<em>v</em>) are examined. Results show that the slit design, normal direction, along with continuous activation, outperforms the rectangular design, parallel direction, and partial activation in reducing pressure peaks. Notably, maximum pressure peaks on the train and tunnel surface exhibit an exponential decay pattern as SB_<em>v</em> increases. The micro-pressure wave 20 m from the tunnel exit decreases by 28% as SB_<em>v</em> increases from 0 to 0.27<em>U</em>. Additionally, maximum slipstream peaks decrease linearly with SB_<em>v</em>, with a more pronounced decline on the near side. While drag on the head and middle cars decreases linearly with increasing SB_<em>v</em>, the tail car experiences a quadratic increase in drag, leading to an overall reduction in total drag. Furthermore, the reduction in side force and the positive lift of the tail car enhances train safety during tunnel passage. Overall, the hybrid suction &amp; blowing technique offer promising prospects for enhancing the aerodynamic performance of high-speed maglev trains in the future.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105961"},"PeriodicalIF":4.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142707032","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}

{"title":"Full-scale experimental investigation of wind loading on ballasted photovoltaic arrays mounted on flat roofs","authors":"Houssam Al Sayegh ,&nbsp;Arindam Gan Chowdhury ,&nbsp;Ioannis Zisis ,&nbsp;Amal Elawady ,&nbsp;Johnny Estephan ,&nbsp;Ameyu Tolera","doi":"10.1016/j.jweia.2024.105963","DOIUrl":"10.1016/j.jweia.2024.105963","url":null,"abstract":"<div><div>Ballasted photovoltaic (PV) systems, in comparison to roof-anchored systems, are gaining notable popularity on commercial flat roofs due to the benefits they provide in evading roof penetration and the associated insulation issues. However, the accurate estimation of the aerodynamic uplift forces and their consequent effects on system responses presents a new design challenge. Moreover, possible dynamic effects, characterized by wind induced vibrations, are not accounted for in the design of PV systems in ASCE 7–22, potentially rendering the code design coefficients unconservative. Additionally, the available literature is based on roof anchored PV systems, while experiments in the literature utilizing ballasted PV systems which have distinct behavior and dynamic properties are very limited. The current study aims for a better evaluation of the behavior of ballasted PV systems and the mitigation efficiency of wind deflectors under simulated extreme wind events. To fill this knowledge gap, a 2 x 2 full-scale ballasted PV array model, equipped with wind deflectors and located on a model flat roofed structure was tested at the Wall of Wind (WOW) Experimental Facility (EF). The experimental campaign consisted of aerodynamic and dynamic tests, which permits pressure measurements on the panels under high Reynolds number flow, realistically influenced by the vibrations of the deflectors, as well as capturing of array's dynamic characteristics. The results show that wind deflectors effectively reduce both net area-averaged and point pressure coefficients, particularly under cornering wind directions. While the top surface pressures remained unchanged with the addition of deflectors, the bottom surface pressures experienced a substantial decrease, and the power spectral densities of pressure fluctuations were significantly reduced. Wind deflectors also proved to be efficient in reducing the correlation of instantaneous aerodynamic pressures occurring at different points, reducing the area-averaged peak pressures on the panels and, consequently, reducing net uplift on the entire array. Moreover, the aerodynamic loads were amplified by up to 30% due to dynamic effects caused by the wind induced vibration of the panels. Finally, from the failure assessment tests, a cascading failure mode was observed where the supports are consequently lifted before the entire system is flipped.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105963"},"PeriodicalIF":4.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142707031","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}

{"title":"Non-Gaussian non-stationary wind speed simulation based on time-varying autoregressive model and maximum entropy method","authors":"Ning Zhao ,&nbsp;Yu Wu ,&nbsp;Fengbo Wu ,&nbsp;Xu Wang ,&nbsp;Shaomin Jia","doi":"10.1016/j.jweia.2024.105960","DOIUrl":"10.1016/j.jweia.2024.105960","url":null,"abstract":"<div><div>Accurate simulation of non-Gaussian nonstationary wind speeds is a prerequisite for the wind resistant design of some nonlinear structures. Due to its efficiency, the time-varying autoregressive (TVAR) model has been extensively employed for simulating non-Gaussian nonstationary processes. Nevertheless, these simulation techniques based on TVAR exhibit suboptimal performance when confronted with nonstationary and highly non-Gaussian processes. Furthermore, they are unable to replicate the bimodal characteristics of specific wind speeds. This paper presents a new method for simulating univariate non-Gaussian nonstationary wind speeds using the TVAR model and the maximum entropy method. Herein, the connection between the statistical moments of input and output processes in TVAR is firstly derived. Secondly, the maximum entropy method is utilized to reconstruct the probability density function of input process and the time-varying translation function is determined. Finally, the translation process theory is applied to generate the input process, which is then input into the TVAR model to output the non-Gaussian nonstationary wind speed. The numerical results demonstrate that the proposed method exhibits superior simulation accuracy for nonstationary and strongly non-Gaussian wind speed processes. Furthermore, it is capable of capturing the bimodal characteristics of certain hardening non-Gaussian nonstationary wind speeds and possesses a broader range of applications.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"256 ","pages":"Article 105960"},"PeriodicalIF":4.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142707380","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}