Pub Date : 2024-10-17DOI: 10.1016/j.jweia.2024.105910
Yujiang Shi , Tao Tao , Haokai Wu , Yao-Ran Chen , Zhaolong Han , Dai Zhou , Wen-Li Chen , Yong Cao
Compared to traditional CFD models, weather research and forecasting model (WRF) can more realistically reproduce complex spatio-temporally varying wind fields under extreme weather disasters like typhoon. However, the large-eddy simulation mode of WRF (WRF-LES) to predict engineering-scale turbulence has yet to be clarified in terms of different turbulence models. This study selected a three-dimensional hill as the research object. We focus on separated flow past a 3D hill to systematically revisit the influence of four turbulence models (SMAG, TKE, NBA1, NBA2). The results show that four classical turbulence models under the default conditions can only reproduce the turbulent structure of the post-hill separation to a certain extent and that the nonlinear models (NBA1 and NBA2) simulate more hairpin vortices and small-scale vortex structures than the linear models (SMAG and TKE). Then, the parameter sensitivity is clarified by adjusting key parameters of four classical WRF-LES turbulence models. The results show that the ability of the linear models to simulate the separated flow and small-scale vortex structure is sensitive to the vortex viscosity coefficient. Once the nonlinear models are used, the simulation results are insensitive to the backscatter coefficient variation.
{"title":"Assessment of turbulence model effects on WRF-LES of separated turbulent flows past a 3D hill","authors":"Yujiang Shi , Tao Tao , Haokai Wu , Yao-Ran Chen , Zhaolong Han , Dai Zhou , Wen-Li Chen , Yong Cao","doi":"10.1016/j.jweia.2024.105910","DOIUrl":"10.1016/j.jweia.2024.105910","url":null,"abstract":"<div><div>Compared to traditional CFD models, weather research and forecasting model (WRF) can more realistically reproduce complex spatio-temporally varying wind fields under extreme weather disasters like typhoon. However, the large-eddy simulation mode of WRF (WRF-LES) to predict engineering-scale turbulence has yet to be clarified in terms of different turbulence models. This study selected a three-dimensional hill as the research object. We focus on separated flow past a 3D hill to systematically revisit the influence of four turbulence models (SMAG, TKE, NBA1, NBA2). The results show that four classical turbulence models under the default conditions can only reproduce the turbulent structure of the post-hill separation to a certain extent and that the nonlinear models (NBA1 and NBA2) simulate more hairpin vortices and small-scale vortex structures than the linear models (SMAG and TKE). Then, the parameter sensitivity is clarified by adjusting key parameters of four classical WRF-LES turbulence models. The results show that the ability of the linear models to simulate the separated flow and small-scale vortex structure is sensitive to the vortex viscosity coefficient. Once the nonlinear models are used, the simulation results are insensitive to the backscatter coefficient variation.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105910"},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444911","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 : 2024-10-17DOI: 10.1016/j.jweia.2024.105918
Zhanbiao Zhang, Fuyou Xu, Yuqi Wang, Xu Wang
The vortex-induced vibration (VIV) characteristics and fluid-structure interaction mechanism of a 4:1 rectangular prism is investigated in this study based on large-eddy simulations. Variations of the vibration amplitude, vortex-induced force, and surface pressure with the inflow velocity (U∗) are analyzed. Some significant questions regarding the VIV responses are raised and explained based on dynamic mode decomposition (DMD) and phase analyses of the flow fields. The cooperative shedding process of the motion-induced leading-edge vortex and the Karmon-type trailing-edge vortex that sustains the VIV is identified in the DMD mode. It is found that the phase difference between the leading and trailing-edge vortices in the near wake increases with U∗, leading to the eventual disappearance of VIV at a critical U∗. The root-mean-squared lift coefficient (CL_rms) reaches its highest value in the initial phase of lock-in range, and then shows a monotonic reduction with increasing U∗. However, the structure could maintain a relatively large vibration amplitude until VIV disappears, even though the CL_rms may be as low as that for the static case. This phenomenon is explained in detail based on the variations in phase distributions of the surface pressure with increasing U∗.
{"title":"Fluid-structure interaction analysis of a 4:1 rectangular prism undergoing vortex-induced vibration","authors":"Zhanbiao Zhang, Fuyou Xu, Yuqi Wang, Xu Wang","doi":"10.1016/j.jweia.2024.105918","DOIUrl":"10.1016/j.jweia.2024.105918","url":null,"abstract":"<div><div>The vortex-induced vibration (VIV) characteristics and fluid-structure interaction mechanism of a 4:1 rectangular prism is investigated in this study based on large-eddy simulations. Variations of the vibration amplitude, vortex-induced force, and surface pressure with the inflow velocity (<em>U</em>∗) are analyzed. Some significant questions regarding the VIV responses are raised and explained based on dynamic mode decomposition (DMD) and phase analyses of the flow fields. The cooperative shedding process of the motion-induced leading-edge vortex and the Karmon-type trailing-edge vortex that sustains the VIV is identified in the DMD mode. It is found that the phase difference between the leading and trailing-edge vortices in the near wake increases with <em>U</em>∗, leading to the eventual disappearance of VIV at a critical <em>U</em>∗. The root-mean-squared lift coefficient (<em>C</em><sub><em>L</em></sub>_<em>rms</em>) reaches its highest value in the initial phase of lock-in range, and then shows a monotonic reduction with increasing <em>U</em>∗. However, the structure could maintain a relatively large vibration amplitude until VIV disappears, even though the <em>C</em><sub><em>L</em></sub>_<em>rms</em> may be as low as that for the static case. This phenomenon is explained in detail based on the variations in phase distributions of the surface pressure with increasing <em>U</em>∗.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105918"},"PeriodicalIF":4.2,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444910","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}
By incorporating extra load-carrying main cables, multi-cable suspension bridges provide increased flexibility in adjusting structural dynamic characteristics, and new possible solutions to the flutter instability problem of long-span bridges. Based on a multi-cable suspension bridge, this paper presents a particular insight into the dynamic characteristics which was contrast with double-cable suspension bridge. Furthermore, the influence of stiffness distribution and sag-span ratio of main cables on the dynamic characteristics was also studied. It is shown that due to the different contribution of the main cables, multi-cable suspension bridge has various torsional modes with similar vibration shapes of the stiffening girder, which is quite different from double-cable suspension bridge. Changes in stiffness distribution of main cables also have significant effects on the form of these torsional modes. On this basis, the flutter performance of multi-cable suspension bridge is studied by modality-driven method. The results indicate that the flutter critical wind speed increases with the increase of sag-span ratio and stiffness ratio of inner and outer main cables, and multi-cable suspension bridge can obtain better flutter performance than double-cable suspension bridge with appropriate stiffness distribution. The change of stiffness distribution and sag-span ratio may lead to the transition of flutter dominant mode.
{"title":"Effect and mechanism of stiffness distribution and sag-span ratio of main cables on structural dynamic characteristics and flutter performance of multi-cable suspension bridges","authors":"Yunliang Shi, Yongxin Yang, Jinbo Zhu, Jinjie Zhang","doi":"10.1016/j.jweia.2024.105919","DOIUrl":"10.1016/j.jweia.2024.105919","url":null,"abstract":"<div><div>By incorporating extra load-carrying main cables, multi-cable suspension bridges provide increased flexibility in adjusting structural dynamic characteristics, and new possible solutions to the flutter instability problem of long-span bridges. Based on a multi-cable suspension bridge, this paper presents a particular insight into the dynamic characteristics which was contrast with double-cable suspension bridge. Furthermore, the influence of stiffness distribution and sag-span ratio of main cables on the dynamic characteristics was also studied. It is shown that due to the different contribution of the main cables, multi-cable suspension bridge has various torsional modes with similar vibration shapes of the stiffening girder, which is quite different from double-cable suspension bridge. Changes in stiffness distribution of main cables also have significant effects on the form of these torsional modes. On this basis, the flutter performance of multi-cable suspension bridge is studied by modality-driven method. The results indicate that the flutter critical wind speed increases with the increase of sag-span ratio and stiffness ratio of inner and outer main cables, and multi-cable suspension bridge can obtain better flutter performance than double-cable suspension bridge with appropriate stiffness distribution. The change of stiffness distribution and sag-span ratio may lead to the transition of flutter dominant mode.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105919"},"PeriodicalIF":4.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441516","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 : 2024-10-15DOI: 10.1016/j.jweia.2024.105923
Myungsik Tai , Hyeonwoo Hwang , Shinkyu Jeong , Jongseo Bak , Donghun Park
Although the classical method is widely used for wall interference correction in wind tunnel testing, its reliability and accuracy for complex and unconventional geometries are rather limited. Studies on the evaluation of wall interference and the improvement of correction methods are desirable to enhance the reliability and generality for various geometric configurations. This study proposes a wall interference correction framework based on a deep neural network (DNN) ensemble using data obtained from the numerical panel method. The panel method is validated by comparing the results with those of Reynolds-averaged Navier-Stokes simulations. An automated process was established to generate a large amount of training data, and 600,000 datasets were generated based on the geometric parameters of the wind tunnel, test model, and angles of attack. The input variables of the DNN were determined through sensitivity analysis of the data. To alleviate the randomness of the initial weights and data distribution in the generation process of the DNN model, 20 DNNs with the same multi-layer perceptron structure were trained, and a DNN ensemble model was constructed using five ensemble members with high predictability. The accuracy of the DNN-ensemble based correction models were evaluated by comparing the correction results for the testing data.
{"title":"Feasibility study of data-driven wall interference correction framework for subsonic wind tunnel","authors":"Myungsik Tai , Hyeonwoo Hwang , Shinkyu Jeong , Jongseo Bak , Donghun Park","doi":"10.1016/j.jweia.2024.105923","DOIUrl":"10.1016/j.jweia.2024.105923","url":null,"abstract":"<div><div>Although the classical method is widely used for wall interference correction in wind tunnel testing, its reliability and accuracy for complex and unconventional geometries are rather limited. Studies on the evaluation of wall interference and the improvement of correction methods are desirable to enhance the reliability and generality for various geometric configurations. This study proposes a wall interference correction framework based on a deep neural network (DNN) ensemble using data obtained from the numerical panel method. The panel method is validated by comparing the results with those of Reynolds-averaged Navier-Stokes simulations. An automated process was established to generate a large amount of training data, and 600,000 datasets were generated based on the geometric parameters of the wind tunnel, test model, and angles of attack. The input variables of the DNN were determined through sensitivity analysis of the data. To alleviate the randomness of the initial weights and data distribution in the generation process of the DNN model, 20 DNNs with the same multi-layer perceptron structure were trained, and a DNN ensemble model was constructed using five ensemble members with high predictability. The accuracy of the DNN-ensemble based correction models were evaluated by comparing the correction results for the testing data.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105923"},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437661","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 : 2024-10-15DOI: 10.1016/j.jweia.2024.105920
Puyang Zhang , Guangjun Gao , Jiabin Wang , Wenfei Shang , Liu Cao , Xinchao Su
This paper studies the aerodynamic characteristics of high-speed trains (HSTs) featuring aerodynamic braking plates installed on the streamlined sections, employing the improved delayed detached eddy simulation (IDDES) method at Re = 5.0 × 105. The precision of the numerical simulation methodology has been validated through reduced-scale wind tunnel experiments. A comparative analysis has been conducted on the characteristics of slipstream, wake flow, and upper flow between the original configuration (OC) and the braking configuration (BC) of the HSTs. The findings reveal that the application of braking plates promotes significant separation phenomena around the HSTs, enhancing the slipstream velocity distribution. In the BC, compared to the OC, the maximum value of the time-averaged slipstream velocity has increased by approximately 134.9% and 76.8% at the trackside and platform positions, respectively. Additionally, the TSI value of the slipstream velocity shows increases of around 100.4% and 210.4% at the trackside and platform positions, respectively. Meanwhile, the turbulence fluctuations within the wake region have been enhanced, with the formation of a longitudinal vortex alongside the railway subgrade, whose core nearly covers the TSI positions. Notably, obvious shifts occur within the upper flow field, which significantly strengthens both flow turbulence and slipstream velocity, potentially influencing components on the upper surface of HSTs, such as the pantograph. The deployment of braking plates contributes to a significant increase in overall vehicle pressure drag, thereby enhancing the train's aerodynamic drag. Relative to the OC, the aerodynamic drag of the HST has increased by approximately 235.4% in the BC.
本文采用改进的延迟分离涡模拟（IDDES）方法，在 Re = 5.0 × 105 的条件下研究了高速列车（HST）的气动特性，该列车的流线型部分安装了气动制动板。通过缩小尺度的风洞实验验证了数值模拟方法的精确性。对 HST 原始配置（OC）和制动配置（BC）之间的滑流、尾流和上层流特性进行了对比分析。研究结果表明，制动板的应用促进了 HST 周围的显著分离现象，增强了滑流速度分布。在 BC 中，与 OC 相比，轨道边和平台位置的时间平均滑流速度最大值分别增加了约 134.9% 和 76.8%。此外，滑流速度的 TSI 值在轨道边和平台位置分别增加了约 100.4% 和 210.4%。同时，尾流区域内的湍流波动也增强了，在铁路路基旁形成了一个纵向涡流，其核心几乎覆盖了 TSI 位置。值得注意的是，上部流场发生了明显的变化，极大地增强了流动湍流和滑流速度，可能会影响 HST 上表面的部件，如受电弓。制动板的展开会显著增加整个车辆的压力阻力，从而增强列车的空气阻力。与正常运行时相比，在 BC 阶段 HST 的空气阻力增加了约 235.4%。
{"title":"Numerical investigation on the impact of aerodynamic braking plates positioned at streamlined sections on the slipstream and wake flow of the high-speed train based on train-fixed reference frame","authors":"Puyang Zhang , Guangjun Gao , Jiabin Wang , Wenfei Shang , Liu Cao , Xinchao Su","doi":"10.1016/j.jweia.2024.105920","DOIUrl":"10.1016/j.jweia.2024.105920","url":null,"abstract":"<div><div>This paper studies the aerodynamic characteristics of high-speed trains (HSTs) featuring aerodynamic braking plates installed on the streamlined sections, employing the improved delayed detached eddy simulation (IDDES) method at Re = 5.0 × 10<sup>5</sup>. The precision of the numerical simulation methodology has been validated through reduced-scale wind tunnel experiments. A comparative analysis has been conducted on the characteristics of slipstream, wake flow, and upper flow between the original configuration (OC) and the braking configuration (BC) of the HSTs. The findings reveal that the application of braking plates promotes significant separation phenomena around the HSTs, enhancing the slipstream velocity distribution. In the BC, compared to the OC, the maximum value of the time-averaged slipstream velocity has increased by approximately 134.9% and 76.8% at the trackside and platform positions, respectively. Additionally, the TSI value of the slipstream velocity shows increases of around 100.4% and 210.4% at the trackside and platform positions, respectively. Meanwhile, the turbulence fluctuations within the wake region have been enhanced, with the formation of a longitudinal vortex alongside the railway subgrade, whose core nearly covers the TSI positions. Notably, obvious shifts occur within the upper flow field, which significantly strengthens both flow turbulence and slipstream velocity, potentially influencing components on the upper surface of HSTs, such as the pantograph. The deployment of braking plates contributes to a significant increase in overall vehicle pressure drag, thereby enhancing the train's aerodynamic drag. Relative to the OC, the aerodynamic drag of the HST has increased by approximately 235.4% in the BC.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105920"},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437660","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 : 2024-10-15DOI: 10.1016/j.jweia.2024.105926
Yi Hui , Zhenhuai Yang , Chao Xia , Yi Su , Shaopeng Li
Although pendulum tuned mass damper (PTMD) is one of the most classic and commonly used vibration control devices, it has clear limitation due to the natural feature of linear TMD. Additional stoppers for the pendulum string (PTMD-AS) were proposed and introduced to improve the PTMD's performance by triggering its nonlinearity. A 2-DOF model was established to analyze the dynamic response of the system subjected to harmonic excitation, and the governing equations were formulated using the Lagrange equation. The extended incremental harmonic balance (EIHB) method and the Runge-Kutta (R-K) method were utilized to calculate the frequency response and time history of the system. Nonlinear dynamic characteristics of the pendulum with stiffness hardening were explored in detail. Sensitivity analyses were performed to investigate the effect of stopper position. It was found that aperiodic responses or multiple solutions could be induced when the pendulum underwent significant stiffness hardening upon passing the additional stoppers. Finally, the effectiveness and robustness of PTMD-AS are demonstrated in a numerical simulation of a high-rise building subjected to random wind excitation based on wind tunnel experiments.
{"title":"Study on vibration control performance of pendulum TMD with additional stoppers and its application on high-rise buildings","authors":"Yi Hui , Zhenhuai Yang , Chao Xia , Yi Su , Shaopeng Li","doi":"10.1016/j.jweia.2024.105926","DOIUrl":"10.1016/j.jweia.2024.105926","url":null,"abstract":"<div><div>Although pendulum tuned mass damper (PTMD) is one of the most classic and commonly used vibration control devices, it has clear limitation due to the natural feature of linear TMD. Additional stoppers for the pendulum string (PTMD-AS) were proposed and introduced to improve the PTMD's performance by triggering its nonlinearity. A 2-DOF model was established to analyze the dynamic response of the system subjected to harmonic excitation, and the governing equations were formulated using the Lagrange equation. The extended incremental harmonic balance (EIHB) method and the Runge-Kutta (R-K) method were utilized to calculate the frequency response and time history of the system. Nonlinear dynamic characteristics of the pendulum with stiffness hardening were explored in detail. Sensitivity analyses were performed to investigate the effect of stopper position. It was found that aperiodic responses or multiple solutions could be induced when the pendulum underwent significant stiffness hardening upon passing the additional stoppers. Finally, the effectiveness and robustness of PTMD-AS are demonstrated in a numerical simulation of a high-rise building subjected to random wind excitation based on wind tunnel experiments.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105926"},"PeriodicalIF":4.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441515","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.2024.105916
Xin Yang , Jie Li
Modeling and simulation of atmospheric turbulence in coastal areas has emerged as a prominent area of research in recent years. This study presents a physical stochastic model to describe the horizontal coherence of fluctuating wind fields within the physical stochastic modeling frame. Based on the one-dimensional stochastic Fourier spectrum and isotropic turbulence theory, the horizontal coherence for fluctuating wind fields is expressed as a random function, with its probability information determined by the physical mechanism/background. The proposed physical stochastic model directly depicts the stochastic time series thereby enabling it to capture all probability information in detail comprehensively. The proposed model is numerically validated with the measured data obtained from an observation array constructed in Southeast China. This investigation holds significant potential for its application in wind-resistance design and reliability assessment of long-span structures.
{"title":"A physical stochastic model of near-surface fluctuating wind fields","authors":"Xin Yang , Jie Li","doi":"10.1016/j.jweia.2024.105916","DOIUrl":"10.1016/j.jweia.2024.105916","url":null,"abstract":"<div><div>Modeling and simulation of atmospheric turbulence in coastal areas has emerged as a prominent area of research in recent years. This study presents a physical stochastic model to describe the horizontal coherence of fluctuating wind fields within the physical stochastic modeling frame. Based on the one-dimensional stochastic Fourier spectrum and isotropic turbulence theory, the horizontal coherence for fluctuating wind fields is expressed as a random function, with its probability information determined by the physical mechanism/background. The proposed physical stochastic model directly depicts the stochastic time series thereby enabling it to capture all probability information in detail comprehensively. The proposed model is numerically validated with the measured data obtained from an observation array constructed in Southeast China. This investigation holds significant potential for its application in wind-resistance design and reliability assessment of long-span structures.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105916"},"PeriodicalIF":4.2,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433396","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.2024.105917
Wenlong Chen , Guohao Deng , Hanfeng Wang
To control the aerodynamic forces and near wake of a 3D wall-mounted square cylinder with an aspect ratio H/d = 5, pulsing slot suction is employed at its free-end leading edge. The present experiment is investigated in a wind tunnel with Reynolds number Re = 2.74 × 104. The pulsing suction ratio f∗, defined as the ratio of the pulsing suction frequency fs to the vortex shedding frequency fv, ranges from 0 to 1.6, corresponding to a momentum coefficient range of 0–0.03. The pulsing slot suction can greatly reduce the overall fluctuating drag and fluctuating lift of the cylinder. Aerodynamic suppression effect enhances with increasing f∗, and becomes stable for f∗ ≥ 0.6 ( ≥ 0.014). At f∗ = 0.6, the overall , and are reduced by 2.7%, 22.2% and 50.1%, respectively. The pulsing suction control causes periodic reattachment of the free-end shear flow to the cylinder's free end, forming large-scale vortex structures downstream of the cylinder, and enhancing the momentum exchange between wake and free flow. On the other hand, although the strength of spanwise vortex shedding is obviously weakened, its frequency remains unchanged at all tested f∗. Results from particle image velocimetry (PIV) show that the turbulent kinetic energy in the cylinder wake is significantly reduced. Analyses using the proper orthogonal decomposition (POD) demonstrate that the periodicity of near-wake vortex structure is significantly suppressed.
{"title":"Control of the aerodynamic forces and the near wake of a 3D wall-mounted square cylinder using pulsing slot suction at its free end","authors":"Wenlong Chen , Guohao Deng , Hanfeng Wang","doi":"10.1016/j.jweia.2024.105917","DOIUrl":"10.1016/j.jweia.2024.105917","url":null,"abstract":"<div><div>To control the aerodynamic forces and near wake of a 3D wall-mounted square cylinder with an aspect ratio <em>H</em>/<em>d</em> = 5, pulsing slot suction is employed at its free-end leading edge. The present experiment is investigated in a wind tunnel with Reynolds number <em>Re</em> = 2.74 × 10<sup>4</sup>. The pulsing suction ratio <em>f<sup>∗</sup></em>, defined as the ratio of the pulsing suction frequency <em>f</em><sub><em>s</em></sub> to the vortex shedding frequency <em>f</em><sub><em>v</em></sub>, ranges from 0 to 1.6, corresponding to a momentum coefficient <span><math><mrow><msub><mi>C</mi><mi>μ</mi></msub></mrow></math></span> range of 0–0.03. The pulsing slot suction can greatly reduce the overall fluctuating drag <span><math><mrow><msubsup><mi>C</mi><mi>d</mi><mo>′</mo></msubsup></mrow></math></span> and fluctuating lift <span><math><msubsup><mi>C</mi><mi>l</mi><mo>'</mo></msubsup></math></span> of the cylinder. Aerodynamic suppression effect enhances with increasing <em>f<sup>∗</sup></em>, and becomes stable for <em>f<sup>∗</sup></em> ≥ 0.6 (<span><math><mrow><msub><mi>C</mi><mi>μ</mi></msub></mrow></math></span> ≥ 0.014). At <em>f<sup>∗</sup></em> = 0.6, the overall <span><math><mrow><mover><msub><mi>C</mi><mi>d</mi></msub><mo>‾</mo></mover></mrow></math></span>, <span><math><mrow><msubsup><mi>C</mi><mi>d</mi><mo>′</mo></msubsup></mrow></math></span> and <span><math><msubsup><mi>C</mi><mi>l</mi><mo>'</mo></msubsup></math></span> are reduced by 2.7%, 22.2% and 50.1%, respectively. The pulsing suction control causes periodic reattachment of the free-end shear flow to the cylinder's free end, forming large-scale vortex structures downstream of the cylinder, and enhancing the momentum exchange between wake and free flow. On the other hand, although the strength of spanwise vortex shedding is obviously weakened, its frequency remains unchanged at all tested <em>f<sup>∗</sup></em>. Results from particle image velocimetry (PIV) show that the turbulent kinetic energy in the cylinder wake is significantly reduced. Analyses using the proper orthogonal decomposition (POD) demonstrate that the periodicity of near-wake vortex structure is significantly suppressed.</div></div>","PeriodicalId":54752,"journal":{"name":"Journal of Wind Engineering and Industrial Aerodynamics","volume":"254 ","pages":"Article 105917"},"PeriodicalIF":4.2,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434123","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.2024.105922
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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号