Pub Date : 2021-06-01DOI: 10.12989/WAS.2021.32.6.551
Shengli Li, Jun Liang, P. Guo, Xidong Wang, Panjie Li
Refer to wind turbine airfoil wind tunnel test and consider the characteristics of wind generated by a moving vehicle, a new test method for wind turbine airfoil aerodynamic performance is proposed in this paper. Because of the relativity of motion, the vehicle will generate a relative wind field in the process of motion. Thus, the aerodynamic performance of wind turbine airfoil can be investigated using a transiting test method. In this study, a transiting test method is systematically introduced, the processing method of test data is discussed in detail, and the influence of vehicle vibration and end plate on the test results is evaluated. Three independent repeated tests are conducted, and the influence of natural wind is analyzed to eliminate the instability effect. The feasibility of the proposed test method is then verified by comparing its results with the results of wind tunnel test.
{"title":"A novel test method for the aerodynamic performance ofwind turbine airfoil using wind generated by a moving vehicle","authors":"Shengli Li, Jun Liang, P. Guo, Xidong Wang, Panjie Li","doi":"10.12989/WAS.2021.32.6.551","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.6.551","url":null,"abstract":"Refer to wind turbine airfoil wind tunnel test and consider the characteristics of wind generated by a moving \u0000vehicle, a new test method for wind turbine airfoil aerodynamic performance is proposed in this paper. Because of the relativity \u0000of motion, the vehicle will generate a relative wind field in the process of motion. Thus, the aerodynamic performance of wind \u0000turbine airfoil can be investigated using a transiting test method. In this study, a transiting test method is systematically introduced, the processing method of test data is discussed in detail, and the influence of vehicle vibration and end plate on the test results is evaluated. Three independent repeated tests are conducted, and the influence of natural wind is analyzed to eliminate the instability effect. The feasibility of the proposed test method is then verified by comparing its results with the results of wind tunnel test.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42101416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-06-01DOI: 10.12989/WAS.2021.32.6.563
S. Tuhta
In this study was investigated of possibility using the recorded micro tremor data on ground level as ambient vibration input excitation data for investigation and application Experimental Modal Analysis (EMA) on the bench-scale earthquake simulator (The Quanser Shake Table) for model wind tunnel. As known EMA methods (such as EFDD, SSI and so on) are supposed to deal with the ambient responses. For this purpose, analytical and experimental modal analysis of a model wind tunnel for dynamic characteristics was evaluated. 3D Finite element model of the building was evaluated for the model wind tunnel based on the design drawing. Ambient excitation was provided by shake table from the recorded micro tremor ambient vibration data on ground level. Enhanced Frequency Domain Decomposition is used for the output only modal identification. From this study, best correlation is found between mode shapes. Natural frequencies and analytical frequencies in average (only) 2.5% are differences.
{"title":"Analytical and experimental modal analysis of model wind tunnel using microtremor excitation","authors":"S. Tuhta","doi":"10.12989/WAS.2021.32.6.563","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.6.563","url":null,"abstract":"In this study was investigated of possibility using the recorded micro tremor data on ground level as ambient \u0000vibration input excitation data for investigation and application Experimental Modal Analysis (EMA) on the bench-scale earthquake simulator (The Quanser Shake Table) for model wind tunnel. As known EMA methods (such as EFDD, SSI and so on) are supposed to deal with the ambient responses. For this purpose, analytical and experimental modal analysis of a model wind tunnel for dynamic characteristics was evaluated. 3D Finite element model of the building was evaluated for the model wind tunnel based on the design drawing. Ambient excitation was provided by shake table from the recorded micro tremor ambient vibration data on ground level. Enhanced Frequency Domain Decomposition is used for the output only modal identification. From this study, best correlation is found between mode shapes. Natural frequencies and analytical frequencies in average (only) 2.5% are differences.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45403088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-06-01DOI: 10.12989/WAS.2021.32.6.587
Cheng Xiang, Airong Chen, Li Qiheng, R. Ma
Wind speed is one of the most critical parameters in predicting structural performance under wind effects. In most of the current standards and codes, the design reference wind speed is usually determined by fitting a typical probability distribution model based on the historical wind speed data. However, a single distribution model is generally insufficient to reflect the regional differences in wind characteristics. Therefore, in this research, the optimal probability is selected to determine the extreme wind speed in different regions in China based on the fourth-order linear moment method (FLMM). Firstly, several probability models for estimating extreme wind speed distribution are introduced. Then, the optimal model, as well as the relative parameters, are determined by the linear moments (L-moments) method, and the one with the minimum value of the fourth-order linear moment between the probability model and the sample is taken as the optimal distribution. Finally, the extreme wind speed of each meteorological station is estimated according to the obtained optimal distribution, and the results are compared with the recorded extreme wind speed of typical metrological stations as well as that in the previous version of specification (JTG/T D60-01-2004). Compared with the traditional method that adopting a single distribution model-based wind speed estimation, the extreme wind speed obtained by the proposed method possessed higher accuracy.
{"title":"Research on the probability model of basic wind speed estimation in China","authors":"Cheng Xiang, Airong Chen, Li Qiheng, R. Ma","doi":"10.12989/WAS.2021.32.6.587","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.6.587","url":null,"abstract":"Wind speed is one of the most critical parameters in predicting structural performance under wind effects. In most of the current standards and codes, the design reference wind speed is usually determined by fitting a typical probability distribution model based on the historical wind speed data. However, a single distribution model is generally insufficient to reflect the regional differences in wind characteristics. Therefore, in this research, the optimal probability is selected to determine \u0000the extreme wind speed in different regions in China based on the fourth-order linear moment method (FLMM). Firstly, several probability models for estimating extreme wind speed distribution are introduced. Then, the optimal model, as well as the relative parameters, are determined by the linear moments (L-moments) method, and the one with the minimum value of the fourth-order linear moment between the probability model and the sample is taken as the optimal distribution. Finally, the extreme wind speed of each meteorological station is estimated according to the obtained optimal distribution, and the results are \u0000compared with the recorded extreme wind speed of typical metrological stations as well as that in the previous version of specification (JTG/T D60-01-2004). Compared with the traditional method that adopting a single distribution model-based wind speed estimation, the extreme wind speed obtained by the proposed method possessed higher accuracy.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48000445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-06-01DOI: 10.12989/WAS.2021.32.6.521
S. Mandal, S. Dalui, S. Bhattacharjya
In the present study, the well-adopted practice of minor aerodynamic modifications (chamfered corner and rounded corner) has been introduced on widely used irregular U plan shaped tall building to minimize the wind induced responses and also to give a good aesthetics. The necessary design inputs for a wind resistance design such as force coefficient and pressure coefficients have been well explored and illustrated graphically to provide a complete guideline to the designer. The randomness of wind directionality has a significant impact on tall structures, which is generally not detailed in existing design codes, is incorporated by considering wind directions ranging from 0° to 180° at an interval of 15°. Computational fluid dynamics (CFD) has been utilized to simulate wind flow using two turbulence models, i.e., k-epsilon and Shear Stress Transport. The model has been validated by comparing the results of a published research article on a U-shaped building without corner modification. The grid independence study has been done to check the reliability and accuracy of the analysis results. Since such study of wind directionality on corner modified U-shaped building is not observed in the existing literature, it constitutes the uniqueness of the present study. A significant reduction in force coefficient has been achieved by implementing modification, but the faces of those updated corners mostly been attracted by excessive pressure. This indicates the necessity of proper cladding configurations. The rounded corner buildings are turning out to be more effective when compared to the chamfered corner for reducing wind load.
{"title":"Wind induced response of corner modified 'U' plan shaped tall building","authors":"S. Mandal, S. Dalui, S. Bhattacharjya","doi":"10.12989/WAS.2021.32.6.521","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.6.521","url":null,"abstract":"In the present study, the well-adopted practice of minor aerodynamic modifications (chamfered corner and rounded corner) has been introduced on widely used irregular U plan shaped tall building to minimize the wind induced responses and also to give a good aesthetics. The necessary design inputs for a wind resistance design such as force coefficient and pressure coefficients have been well explored and illustrated graphically to provide a complete guideline to the designer. The randomness of wind directionality has a significant impact on tall structures, which is generally not detailed in existing design codes, is incorporated by considering wind directions ranging from 0° to 180° at an interval of 15°. Computational fluid dynamics (CFD) has been utilized to simulate wind flow using two turbulence models, i.e., k-epsilon and Shear Stress Transport. The model has been validated by comparing the results of a published research article on a U-shaped building without corner modification. The grid independence study has been done to check the reliability and accuracy of the analysis results. Since such study of wind directionality on corner modified U-shaped building is not observed in the existing literature, it constitutes the uniqueness of the present study. A significant reduction in force coefficient has been achieved by implementing modification, but the faces of those updated corners mostly been attracted by excessive pressure. This indicates the necessity of proper cladding configurations. The rounded corner buildings are turning out to be more effective when compared to the chamfered corner for reducing wind load.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49146116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-05-01DOI: 10.12989/WAS.2021.32.5.509
Haojun Tang, Han Zhang, Wei-chuan Mo, Yongle Li
The streamlined box is a common type of girders for long-span suspension bridges. Spanning deep canyons, long-span bridges are frequently attacked by strong winds with large angles of attack. In this situation, the flow field around the streamlined box changes significantly, leading to reduction of the flutter performance. The wind fairings have different effects on the flutter performance. Therefore, this study examines the flutter performance of box girders with different wind fairings at large angles of attack. Computational fluid dynamics (CFD) simulations were carried out to extract the flutter derivatives, and the critical flutter state of a long-span bridge was determined. Further comparisons of the wind fairings were investigated by a rapid method which is related to the input energy by the aerodynamic force. The results show that a reasonable type of wind fairings could improve the flutter performance of long-span bridges at large angles of attack. For the torsional flutter instability, the wind fairings weaken the adverse effect of the vortex attaching to the girder, and a sharper one could achieve a better result. According to the input energies on the girder with different wind fairings, the symmetrical wind fairings are more beneficial to the flutter performance.
{"title":"Flutter performance of box girders with different wind fairings at large angles of attack","authors":"Haojun Tang, Han Zhang, Wei-chuan Mo, Yongle Li","doi":"10.12989/WAS.2021.32.5.509","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.5.509","url":null,"abstract":"The streamlined box is a common type of girders for long-span suspension bridges. Spanning deep canyons, long-span bridges are frequently attacked by strong winds with large angles of attack. In this situation, the flow field around the streamlined box changes significantly, leading to reduction of the flutter performance. The wind fairings have different effects on the flutter performance. Therefore, this study examines the flutter performance of box girders with different wind fairings at large angles of attack. Computational fluid dynamics (CFD) simulations were carried out to extract the flutter derivatives, and the critical flutter state of a long-span bridge was determined. Further comparisons of the wind fairings were investigated by a rapid method which is related to the input energy by the aerodynamic force. The results show that a reasonable type of wind fairings could improve the flutter performance of long-span bridges at large angles of attack. For the torsional flutter instability, the wind fairings weaken the adverse effect of the vortex attaching to the girder, and a sharper one could achieve a better result. According to the input energies on the girder with different wind fairings, the symmetrical wind fairings are more beneficial to the flutter performance.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49433113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Snow accumulation on the road frequently induces a big traffic problem in the cold snowy region. Accurate prediction on snow distribution is fundamental for solving drifting snow disasters on roads. The present study adopts the transient method to simulate the wind-induced snow distribution on embankment based on the mixture multiphase model and dynamic mesh technique. The simulation and field measurement are compared to confirm the applicability of the simulation. Furthermore, the process of snow accumulation is revealed. The effects of friction velocity and snow concentration on snow accumulation are analyzed to clarify its mechanism. The results show that the simulation agrees well with the field measurement in trends. Moreover, the snow accumulation on the embankment can be approximately divided into three stages with time, the snow firstly deposited on the windward side, then, accumulation occurs on the leeward side which induced by the wake vortex, finally, the snow distribution reaches an equilibrium state with the slope of approximately 7°. The friction velocity and duration have a significant influence on the snow accumulation, and the vortex scale directly affected the snow deposition range on the embankment leeward side.
{"title":"Field measurement and numerical simulation of snow deposition on an embankment in snowdrift","authors":"Wen-jing Ma, Feiqiang Li, Yuanchun Sun, Jianglong Li, Xuanyi Zhou","doi":"10.12989/WAS.2021.32.5.453","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.5.453","url":null,"abstract":"Snow accumulation on the road frequently induces a big traffic problem in the cold snowy region. Accurate prediction on snow distribution is fundamental for solving drifting snow disasters on roads. The present study adopts the transient method to simulate the wind-induced snow distribution on embankment based on the mixture multiphase model and dynamic mesh technique. The simulation and field measurement are compared to confirm the applicability of the simulation. Furthermore, the process of snow accumulation is revealed. The effects of friction velocity and snow concentration on snow accumulation are analyzed to clarify its mechanism. The results show that the simulation agrees well with the field measurement in trends. Moreover, the snow accumulation on the embankment can be approximately divided into three stages with time, the snow firstly deposited on the windward side, then, accumulation occurs on the leeward side which induced by the wake vortex, finally, the snow distribution reaches an equilibrium state with the slope of approximately 7°. The friction velocity and duration have a significant influence on the snow accumulation, and the vortex scale directly affected the snow deposition range on the embankment leeward side.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42059694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-05-01DOI: 10.12989/WAS.2021.32.5.471
Danijel Bosnar, H. Kozmar, S. Pospíšil, M. Macháček
Onshore wind turbines may experience substantially different wind loads depending on their working conditions, i.e., rotation velocity of rotor blades, incoming freestream wind velocity, pitch angle of rotor blades, and yaw angle of the wind-turbine tower. In the present study, aerodynamic loads acting on a horizontal axis wind turbine were accordingly quantified for the high tip speed ratio (TSR) at high yaw angles because these conditions have previously not been adequately addressed. This was analyzed experimentally on a small-scale wind-turbine model in a boundary layer wind tunnel. The wind-tunnel simulation of the neutrally stratified atmospheric boundary layer (ABL) developing above a flat terrain was generated using the Counihan approach. The ABL was simulated to achieve the conditions of a wind-turbine model operating in similar inflow conditions to those of a prototype wind turbine situated in the lower atmosphere, which is another important aspect of the present work. The ABL and wind-turbine simulation length scale factors were the same (S=300) in order to satisfy the Jensen similarity criterion. Aerodynamic loads experienced by the wind-turbine model subjected to the ABL simulation were studied based on the high frequency force balance (HFFB) measurements. Emphasis was put on the thrust force and the bending moment because these two load components have previously proven to be dominant compared to other load components. The results indicate several important findings. The loads were substantially higher for TSR=10 compared to TSR=5.6. In these conditions, a considerable load reduction was achieved by pitching the rotor blades. For the blade pitch angle at 90°, the loads were ten times lower than the loads of the rotating wind-turbine model. For the blade pitch angle at 12°, the loads were at 50% of the rotating wind-turbine model. The loads were reduced by up to 40% through the yawing of the wind-turbine model, which was observed both for the rotating and the parked wind-turbine model.
{"title":"Thrust force and base bending moment acting on a horizontal axis wind turbine with a high tip speed ratio at high yaw angles","authors":"Danijel Bosnar, H. Kozmar, S. Pospíšil, M. Macháček","doi":"10.12989/WAS.2021.32.5.471","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.5.471","url":null,"abstract":"Onshore wind turbines may experience substantially different wind loads depending on their working conditions, i.e., rotation velocity of rotor blades, incoming freestream wind velocity, pitch angle of rotor blades, and yaw angle of the wind-turbine tower. In the present study, aerodynamic loads acting on a horizontal axis wind turbine were accordingly quantified for the high tip speed ratio (TSR) at high yaw angles because these conditions have previously not been adequately addressed. This was analyzed experimentally on a small-scale wind-turbine model in a boundary layer wind tunnel. The wind-tunnel simulation of the neutrally stratified atmospheric boundary layer (ABL) developing above a flat terrain was generated using the Counihan approach. The ABL was simulated to achieve the conditions of a wind-turbine model operating in similar inflow conditions to those of a prototype wind turbine situated in the lower atmosphere, which is another important aspect of the present work. The ABL and wind-turbine simulation length scale factors were the same (S=300) in order to satisfy the Jensen similarity criterion. Aerodynamic loads experienced by the wind-turbine model subjected to the ABL simulation were studied based on the high frequency force balance (HFFB) measurements. Emphasis was put on the thrust force and the bending moment because these two load components have previously proven to be dominant compared to other load components. The results indicate several important findings. The loads were substantially higher for TSR=10 compared to TSR=5.6. In these conditions, a considerable load reduction was achieved by pitching the rotor blades. For the blade pitch angle at 90°, the loads were ten times lower than the loads of the rotating wind-turbine model. For the blade pitch angle at 12°, the loads were at 50% of the rotating wind-turbine model. The loads were reduced by up to 40% through the yawing of the wind-turbine model, which was observed both for the rotating and the parked wind-turbine model.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43241926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-05-01DOI: 10.12989/WAS.2021.32.5.405
Yi Lu, Luo Zhang, Zheng He, Fan Feng, Feng Pan
To gain insight into the wind-induced safety concerns associated with attached tower cranes during the construction of super-tall buildings, a 606 m level frame-core tube super-tall building is selected to investigate the wind-induced vibration response and fragility of an outer-attached tower crane at all stages of construction. The wind velocity time history samples are artificially generated and used to perform dynamic response analyses of the crane to observe the effects of wind velocity and wind direction under its working and non-working resting state. The adverse effects of the relative displacement response at different connection supports are also identified. The wind-resistant fragility curves of the crane are obtained by introducing the concept of incremental dynamic analysis. The results from the investigation indicate that a large relative displacement between the supports can substantially amplify the response of the crane at high levels. Such an effect becomes more serious when the lifting arm is perpendicular to the plane of the connection supports. The flexibility of super-tall buildings should be considered in the design of outer-attached tower cranes, especially for anchorage systems. Fragility analysis can be used to specify the maximum appropriate height of the tower crane for each performance level.
{"title":"Wind-induced vibration fragility of outer-attached tower crane to super-tall buildings: A case study","authors":"Yi Lu, Luo Zhang, Zheng He, Fan Feng, Feng Pan","doi":"10.12989/WAS.2021.32.5.405","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.5.405","url":null,"abstract":"To gain insight into the wind-induced safety concerns associated with attached tower cranes during the construction of super-tall buildings, a 606 m level frame-core tube super-tall building is selected to investigate the wind-induced vibration response and fragility of an outer-attached tower crane at all stages of construction. The wind velocity time history samples are artificially generated and used to perform dynamic response analyses of the crane to observe the effects of wind velocity and wind direction under its working and non-working resting state. The adverse effects of the relative displacement response at different connection supports are also identified. The wind-resistant fragility curves of the crane are obtained by introducing the concept of incremental dynamic analysis. The results from the investigation indicate that a large relative displacement between the supports can substantially amplify the response of the crane at high levels. Such an effect becomes more serious when the lifting arm is perpendicular to the plane of the connection supports. The flexibility of super-tall buildings should be considered in the design of outer-attached tower cranes, especially for anchorage systems. Fragility analysis can be used to specify the maximum appropriate height of the tower crane for each performance level.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43573543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-05-01DOI: 10.12989/WAS.2021.32.5.501
Onur Gunes, E. Altunsu, A. Sarı
The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.
{"title":"Special cases in fatigue analysis of wind turbines","authors":"Onur Gunes, E. Altunsu, A. Sarı","doi":"10.12989/WAS.2021.32.5.501","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.5.501","url":null,"abstract":"The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43496194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-05-01DOI: 10.12989/WAS.2021.32.5.439
A. Merhi, C. Letchford
The concept of Performance objective assessment is extended to wind engineering. This approach applies using the Database-Assisted Design technique, relying on the aerodynamic database provided by the National Institute of Standards and Technology (NIST). A structural model of a low-rise building is analyzed to obtain influence coefficients for internal forces and displacements. Combining these coefficients with time histories of pressure coefficients on the envelope produces time histories of load effects on the structure, for example knee and ridge bending moments, and eave lateral drift. The peak values of such effects are represented by an extreme-value Type I Distribution, which allows the estimation of the gust wind speed leading to the mean hourly extreme loading that cause specific performance objective compromises. Firstly a fully correlated wind field over large tributary areas is assumed and then relaxed to utilize the denser pressure tap data available but with considerably more computational effort. The performance objectives are determined in accordance with the limit state load combinations given in the ASCE 7-16 provisions, particularly the Load and Resistance Factor Design (LRFD) method. The procedure is then repeated for several wind directions and different dominant opening scenarios to determine the cases that produce performance objective criteria. Comparisons with two approaches in ASCE 7 are made.
{"title":"Computational method in database-assisted design for wind engineering with varying performance objectives","authors":"A. Merhi, C. Letchford","doi":"10.12989/WAS.2021.32.5.439","DOIUrl":"https://doi.org/10.12989/WAS.2021.32.5.439","url":null,"abstract":"The concept of Performance objective assessment is extended to wind engineering. This approach applies using the Database-Assisted Design technique, relying on the aerodynamic database provided by the National Institute of Standards and Technology (NIST). A structural model of a low-rise building is analyzed to obtain influence coefficients for internal forces and displacements. Combining these coefficients with time histories of pressure coefficients on the envelope produces time histories of load effects on the structure, for example knee and ridge bending moments, and eave lateral drift. The peak values of such effects are represented by an extreme-value Type I Distribution, which allows the estimation of the gust wind speed leading to the mean hourly extreme loading that cause specific performance objective compromises. Firstly a fully correlated wind field over large tributary areas is assumed and then relaxed to utilize the denser pressure tap data available but with considerably more computational effort. The performance objectives are determined in accordance with the limit state load combinations given in the ASCE 7-16 provisions, particularly the Load and Resistance Factor Design (LRFD) method. The procedure is then repeated for several wind directions and different dominant opening scenarios to determine the cases that produce performance objective criteria. Comparisons with two approaches in ASCE 7 are made.","PeriodicalId":51210,"journal":{"name":"Wind and Structures","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44389771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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