Due to increased demands in transportation development,bridge construction has been extended to areas with complex wind fields.In addition to common flow features such as high wind speeds and strong turbulence intensi...Due to increased demands in transportation development,bridge construction has been extended to areas with complex wind fields.In addition to common flow features such as high wind speeds and strong turbulence intensity,in coastal areas,bridges are likely to be exposed to non-stationary and non-Gaussian high-speed wind fields during hurricane events.Bridges built in mountainous regions will experience varying wind directions,incident angles of attack(AOA),and wind speed variation due to undulating terrain.The complex wind fields are challenging to the bridge engineering community to which accurate calculation methods and suppression measures for bridge vibration are urgently required.In this paper,state-of-the-art research results are introduced through three categories:(a)the distinctive characteristics of complex wind fields in offshore and mountainous areas,(b)the categories of wind-induced vibrations for bridges,and(c)the suppression measures employed in engineering practices.Until now,the studies regarding the coupled bridge vibration in complex wind fields have made considerable progress,but a richer database of actual wind measurement results and more efficient simulation methods still need to be further established.展开更多
The state-of-art Computational Fluid Dynamics （CFD） codes FLUENT is applied in a fine-scale simulation of the wind field over a complex terrain. Several numerical tests are performed to validate the capability of FL...The state-of-art Computational Fluid Dynamics （CFD） codes FLUENT is applied in a fine-scale simulation of the wind field over a complex terrain. Several numerical tests are performed to validate the capability of FLUENT on describing the wind field details over a complex terrain. The results of the numerical tests show that FLUENT can simulate the wind field over extremely complex terrain, which cannot be simulated by mesoscale models. The reason why FLUENT can cope with extremely complex terrain, which can not be coped with by mesoscale models, relies on some particular techniques adopted by FLUENT, such as computer-aided design （CAD） technique, unstructured grid technique and finite volume method. Compared with mesoscale models, FLUENT can describe terrain in much more accurate details and can provide wind simulation results with higher resolution and more accuracy.展开更多
Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Medi-terrane...Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Medi-terranean seas have been carried out for the first time. Traveling synoptic scale vortex wave generation and subsequent evolution of orographic vortices are discovered. Wind fields, spatial distribution of the coefficients of subgrid scale horizontal and vertical turbulence and the Richardson number are calculated. It is shown that the local relief, atmospheric hydrothermodynamics and air-proof tropopause facilitate the generation of β-mesoscale vortex and turbulence amplification in the vicinity of the atmospheric boundary layer and tropopause. Also turbulence parameters distribution in the troposphere has the same nature as in the stratosphere and mesosphere: turbulence coefficients, stratification of the vertical profiles of the Richardson number, thickness of the turbulent and laminar layers.展开更多
The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,...The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,the underlying homogeneity assumption of the typical wind retrieval methods,such as Doppler Beam Swinging(DBS)and Velocity Azimuth Display(VAD)based on a single-lidar,will introduce the measurement uncertainty in complex terrain.In this paper,a new design of a wind measurement campaign involving seven lidars was carried out,which contained the three-lidar-based Virtual Tower(VT)using a time-space synchronization technique and four single-lidars with different elevation angles.This study investigates the performance of VT and VAD measurements under various conditions and evaluates the sensitivity of wind measurement uncertainty of VAD to the horizontal spatial-and probe volume-average effects associated with elevation angles of the laser beam.The inter-comparison results between VT and four VADs show consistent trends with small relative errors under neutral atmospheric conditions with weak wind velocity.Under convective or high Turbulence Intensity(TI)conditions,the relative errors between VT and VAD become larger and more fluctuant.Moreover,it is found that the measurement uncertainty of VAD increases at a given elevation angle with the increasing measurement heights,which is caused by the horizontal homogeneity associated with the conical scanning area.Additionally,the simulated and measured results of four VADs indicate that a larger elevation angle corresponds to a lower measurement uncertainty for a given height.展开更多
复杂地形风电机组建设时易形成高边坡地形,可能严重影响机组的发电量和疲劳寿命。以重庆市某复杂山地风电场为例,基于CDRFG(Consistent Discretizing Random Flow Generation)方法生成大气边界层湍流入口,采用大涡模拟技术重现高边坡复...复杂地形风电机组建设时易形成高边坡地形,可能严重影响机组的发电量和疲劳寿命。以重庆市某复杂山地风电场为例,基于CDRFG(Consistent Discretizing Random Flow Generation)方法生成大气边界层湍流入口,采用大涡模拟技术重现高边坡复杂地形的湍流风场分布,并根据激光测风雷达和测风塔实测数据验证大涡模拟结果的准确性;对比分析了风机平台开挖导致的3种不同高边坡地形下,风机机位湍流风场的差异性,提出了风机平台开挖影响评估指标,深入分析了高边坡地形对风电机组发电效益和安全运行的影响。研究为复杂地形风机平台建设提供了科学保障。展开更多
风场对森林草原火灾的蔓延速度、火势分布以及救援人员的作业安全具有显著影响。本研究旨在探索多普勒测风激光雷达在森林草原火灾救援现场中的应用价值与实际效果。本文以多普勒测风激光雷达在2024年四川雅江“3·15”森林火灾救...风场对森林草原火灾的蔓延速度、火势分布以及救援人员的作业安全具有显著影响。本研究旨在探索多普勒测风激光雷达在森林草原火灾救援现场中的应用价值与实际效果。本文以多普勒测风激光雷达在2024年四川雅江“3·15”森林火灾救援现场的观测数据为基础,首先验证了扫描型测风激光雷达多仰角平面位置显示模式(Plan Position Indicator,PPI)数据采用三维变分法在复杂地形条件下反演三维风场的准确性。在此基础上,利用测风激光雷达PPI扫描模式在雅江3个火点观测的风场信息,对火势蔓延和烟尘的水平扩散进行了初步分析。同时,通过多普勒波束摆动(Doppler Beam Swinging,DBS)模式数据反演火场的垂直风廓线并结合消光系数分析了火场的大气垂直运动。结果表明:以DBS模式反演的垂直风场作为三维变分方法的背景场,在复杂地形条件下反演出的三维风场具有较高的准确性,风速和风向的平均偏差分别为-2.51%和3.92%;火场中的风向决定了火势蔓延和烟尘传播的方向;通过DBS模式反演的火场垂直风廓线,可捕捉到可能引发火势突变的低空急流和动量下传现象,结合消光系数可以进一步分析烟尘在火场中的垂直输送。将多普勒测风激光雷达应用于森林草原火灾现场的风场监测,对提升救援现场指挥管理的科学化水平具有重要意义。展开更多
特高压直流(UHVDC)输电线路地面离子流场的大小是检验电磁环境是否超标的重要判据,对不同风速条件下的地面离子流场的分布进行了计算研究。针对离子流场的计算,提出一种改进迭代上流有限元方法,建立了考虑风速影响的离子流场模型。研究...特高压直流(UHVDC)输电线路地面离子流场的大小是检验电磁环境是否超标的重要判据,对不同风速条件下的地面离子流场的分布进行了计算研究。针对离子流场的计算,提出一种改进迭代上流有限元方法,建立了考虑风速影响的离子流场模型。研究了不同风速对±800 k V输电线路离子流场分布规律的影响。研究表明,地面最大合成场强和离子流密度随风速的增大而增加明显,且风速会使其发生一定偏移。考虑风速为8 m/s时,地面最大合成场强比无风增加了12.64 k V/m,且地面最大离子流密度是无风时的2.65倍。水平风速越大地面合成场强和离子流密度的分布曲线和峰值往背风向偏移越严重,空间其他较远处的合成场强和电荷密度变化不大,且空间合成场强与电荷密度的最大值主要分布于导线周围空间。展开更多
基金The financial support from National Natural Science Foundation of China(Grant No.52078425)。
文摘Due to increased demands in transportation development,bridge construction has been extended to areas with complex wind fields.In addition to common flow features such as high wind speeds and strong turbulence intensity,in coastal areas,bridges are likely to be exposed to non-stationary and non-Gaussian high-speed wind fields during hurricane events.Bridges built in mountainous regions will experience varying wind directions,incident angles of attack(AOA),and wind speed variation due to undulating terrain.The complex wind fields are challenging to the bridge engineering community to which accurate calculation methods and suppression measures for bridge vibration are urgently required.In this paper,state-of-the-art research results are introduced through three categories:(a)the distinctive characteristics of complex wind fields in offshore and mountainous areas,(b)the categories of wind-induced vibrations for bridges,and(c)the suppression measures employed in engineering practices.Until now,the studies regarding the coupled bridge vibration in complex wind fields have made considerable progress,but a richer database of actual wind measurement results and more efficient simulation methods still need to be further established.
基金supported by the National Natural Science Foundation of China(40805004, 40705039 and 90715031)the "Mini-projecton detailed survey and evaluation of wind energy resources"supported by National Climate Center of Chinese Meteoro-logical Administration (CWERA2010002)
文摘The state-of-art Computational Fluid Dynamics （CFD） codes FLUENT is applied in a fine-scale simulation of the wind field over a complex terrain. Several numerical tests are performed to validate the capability of FLUENT on describing the wind field details over a complex terrain. The results of the numerical tests show that FLUENT can simulate the wind field over extremely complex terrain, which cannot be simulated by mesoscale models. The reason why FLUENT can cope with extremely complex terrain, which can not be coped with by mesoscale models, relies on some particular techniques adopted by FLUENT, such as computer-aided design （CAD） technique, unstructured grid technique and finite volume method. Compared with mesoscale models, FLUENT can describe terrain in much more accurate details and can provide wind simulation results with higher resolution and more accuracy.
文摘Numerical modeling and studies of the wind fields at the junction of three continents: over the complex terrains of the South-east Europe, Asia Minor, Middle East, Caucasus and over the Black, Caspian and Medi-terranean seas have been carried out for the first time. Traveling synoptic scale vortex wave generation and subsequent evolution of orographic vortices are discovered. Wind fields, spatial distribution of the coefficients of subgrid scale horizontal and vertical turbulence and the Richardson number are calculated. It is shown that the local relief, atmospheric hydrothermodynamics and air-proof tropopause facilitate the generation of β-mesoscale vortex and turbulence amplification in the vicinity of the atmospheric boundary layer and tropopause. Also turbulence parameters distribution in the troposphere has the same nature as in the stratosphere and mesosphere: turbulence coefficients, stratification of the vertical profiles of the Richardson number, thickness of the turbulent and laminar layers.
基金supported by the National Key Research and Development Program of China[grant number 2021YFC3001902,2022YFB3901705]the National Natural Science Foundation of China[grant number 42106182,U2106210]the Natural Science Foundation of Shandong Province[grant number ZR2021QD052].
文摘The accurate three-dimensional wind field obtained from a Doppler lidar not only helps to comprehend the refined structure of complex airflow but also provides important and valuable solutions for many fields.However,the underlying homogeneity assumption of the typical wind retrieval methods,such as Doppler Beam Swinging(DBS)and Velocity Azimuth Display(VAD)based on a single-lidar,will introduce the measurement uncertainty in complex terrain.In this paper,a new design of a wind measurement campaign involving seven lidars was carried out,which contained the three-lidar-based Virtual Tower(VT)using a time-space synchronization technique and four single-lidars with different elevation angles.This study investigates the performance of VT and VAD measurements under various conditions and evaluates the sensitivity of wind measurement uncertainty of VAD to the horizontal spatial-and probe volume-average effects associated with elevation angles of the laser beam.The inter-comparison results between VT and four VADs show consistent trends with small relative errors under neutral atmospheric conditions with weak wind velocity.Under convective or high Turbulence Intensity(TI)conditions,the relative errors between VT and VAD become larger and more fluctuant.Moreover,it is found that the measurement uncertainty of VAD increases at a given elevation angle with the increasing measurement heights,which is caused by the horizontal homogeneity associated with the conical scanning area.Additionally,the simulated and measured results of four VADs indicate that a larger elevation angle corresponds to a lower measurement uncertainty for a given height.
文摘复杂地形风电机组建设时易形成高边坡地形,可能严重影响机组的发电量和疲劳寿命。以重庆市某复杂山地风电场为例,基于CDRFG(Consistent Discretizing Random Flow Generation)方法生成大气边界层湍流入口,采用大涡模拟技术重现高边坡复杂地形的湍流风场分布,并根据激光测风雷达和测风塔实测数据验证大涡模拟结果的准确性;对比分析了风机平台开挖导致的3种不同高边坡地形下,风机机位湍流风场的差异性,提出了风机平台开挖影响评估指标,深入分析了高边坡地形对风电机组发电效益和安全运行的影响。研究为复杂地形风机平台建设提供了科学保障。
文摘风场对森林草原火灾的蔓延速度、火势分布以及救援人员的作业安全具有显著影响。本研究旨在探索多普勒测风激光雷达在森林草原火灾救援现场中的应用价值与实际效果。本文以多普勒测风激光雷达在2024年四川雅江“3·15”森林火灾救援现场的观测数据为基础,首先验证了扫描型测风激光雷达多仰角平面位置显示模式(Plan Position Indicator,PPI)数据采用三维变分法在复杂地形条件下反演三维风场的准确性。在此基础上,利用测风激光雷达PPI扫描模式在雅江3个火点观测的风场信息,对火势蔓延和烟尘的水平扩散进行了初步分析。同时,通过多普勒波束摆动(Doppler Beam Swinging,DBS)模式数据反演火场的垂直风廓线并结合消光系数分析了火场的大气垂直运动。结果表明:以DBS模式反演的垂直风场作为三维变分方法的背景场,在复杂地形条件下反演出的三维风场具有较高的准确性,风速和风向的平均偏差分别为-2.51%和3.92%;火场中的风向决定了火势蔓延和烟尘传播的方向;通过DBS模式反演的火场垂直风廓线,可捕捉到可能引发火势突变的低空急流和动量下传现象,结合消光系数可以进一步分析烟尘在火场中的垂直输送。将多普勒测风激光雷达应用于森林草原火灾现场的风场监测,对提升救援现场指挥管理的科学化水平具有重要意义。
文摘特高压直流(UHVDC)输电线路地面离子流场的大小是检验电磁环境是否超标的重要判据,对不同风速条件下的地面离子流场的分布进行了计算研究。针对离子流场的计算,提出一种改进迭代上流有限元方法,建立了考虑风速影响的离子流场模型。研究了不同风速对±800 k V输电线路离子流场分布规律的影响。研究表明,地面最大合成场强和离子流密度随风速的增大而增加明显,且风速会使其发生一定偏移。考虑风速为8 m/s时,地面最大合成场强比无风增加了12.64 k V/m,且地面最大离子流密度是无风时的2.65倍。水平风速越大地面合成场强和离子流密度的分布曲线和峰值往背风向偏移越严重,空间其他较远处的合成场强和电荷密度变化不大,且空间合成场强与电荷密度的最大值主要分布于导线周围空间。
