This article deals with generation and application of three-dimensional (3D) atmospheric turbulence field in large aircraft real-time flight simulation. The modeling requirements for the turbulence field of large airc...This article deals with generation and application of three-dimensional (3D) atmospheric turbulence field in large aircraft real-time flight simulation. The modeling requirements for the turbulence field of large aircraft flight simulation are analyzed here. The spatial turbulence field is generated in the frequency domain by using the Monte Carlo method,and then transformed back to the time domain with the 3D inverse Fourier transform. The von Karman model is adopted for an accurate description of the turb...展开更多
Slope variation will significantly affect the characteristics of the wind field around a hill.This paper conducts a large-eddy simulation(LES)on an ideal 3D hill to study the impact of slope on wind field properties.E...Slope variation will significantly affect the characteristics of the wind field around a hill.This paper conducts a large-eddy simulation(LES)on an ideal 3D hill to study the impact of slope on wind field properties.Eight slopes ranging from 10°to 45°at 5°intervals are considered,which covers most conventional hill slopes.The inflow turbulence for the LES is generated by adopting a modified generation method that combines the equilibrium boundary conditions with the Fluent inherent vortex method to improve the simulation accuracy.The time-averaged flow field and the instantaneous vortex structure under the eight slopes are comparatively analyzed.The accuracy of the present method is verified by comparison with experimental data.The slope can affect both the mean and fluctuating wind flow fields around the 3D hill,especially on the hilltop and the leeward side,where a critical slope of 25°can be observed.The fluctuating wind speeds at the tops of steep hills(with slope angles beyond 25°)decrease with increasing slope,while the opposite phenomenon occurs on gentle hills.With increasing slope,the energy of the high-speed descending airflow is enhanced and pushes the separated flow closer to the hill surface,resulting in increased wind speed near the wall boundary on the leeward side and inhibiting the development of turbulence.The vortex shedding trajectory in the wake region becomes wider and longer,suppressing the growth of the mean wind near the wall boundary and enhancing the turbulence intensity.展开更多
This paper based on Reynolds-averaged Navier-Stokes equations standard ?model [1];the surface pressure on the wind field around two adjacent high-rise buildings was numerically simulated with software Fluent. The resu...This paper based on Reynolds-averaged Navier-Stokes equations standard ?model [1];the surface pressure on the wind field around two adjacent high-rise buildings was numerically simulated with software Fluent. The results show that with the influence of adjacent high-rise building, numerical simulation is a good way to study the wind field around high-rise building and the distribution of wind pressure on building’ surface. The pressures on the windward surface are positive with the maximum at 2/3 H height and have lower values on the top and bottom. The pressures on the leeward surface and two sides were negative. Due to the serious flow separation at the corner of building’s windward, the wind field has a high turbulent kinetic energy.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
基于4个台风过程中的长时间序列风速、风方向观测数据,分析研究了近地台风的湍流积分尺度和脉动风速谱等脉动特性。介绍了湍流积分尺度的几种常见的计算方法,基于实测台风数据,分析研究了台风过程中湍流积分尺度的变化以及不同计算方法...基于4个台风过程中的长时间序列风速、风方向观测数据,分析研究了近地台风的湍流积分尺度和脉动风速谱等脉动特性。介绍了湍流积分尺度的几种常见的计算方法,基于实测台风数据,分析研究了台风过程中湍流积分尺度的变化以及不同计算方法的稳定性。根据实测数据计算了纵向脉动风速谱,并与Von-Karm an谱、Davenport谱、S im iu谱和Harris谱等经验谱进行了比较,给出了最适合描述台风纵向脉动风速谱的经验谱。还计算了横向脉动风速功率谱,并与基于各向同性湍流理论推导出的水平横向脉动风速谱进行了对比。展开更多
文摘This article deals with generation and application of three-dimensional (3D) atmospheric turbulence field in large aircraft real-time flight simulation. The modeling requirements for the turbulence field of large aircraft flight simulation are analyzed here. The spatial turbulence field is generated in the frequency domain by using the Monte Carlo method,and then transformed back to the time domain with the 3D inverse Fourier transform. The von Karman model is adopted for an accurate description of the turb...
基金supported by the National Key R&D Plan of China(No.2018YFB1501104)the National Natural Science Foundation of China(Grant No.52278511)+1 种基金the Natural Science Foundation of Hebei Province(No.E2021210053)the Young Backbone Teacher Cultivation Program of Henan University of Technology.
文摘Slope variation will significantly affect the characteristics of the wind field around a hill.This paper conducts a large-eddy simulation(LES)on an ideal 3D hill to study the impact of slope on wind field properties.Eight slopes ranging from 10°to 45°at 5°intervals are considered,which covers most conventional hill slopes.The inflow turbulence for the LES is generated by adopting a modified generation method that combines the equilibrium boundary conditions with the Fluent inherent vortex method to improve the simulation accuracy.The time-averaged flow field and the instantaneous vortex structure under the eight slopes are comparatively analyzed.The accuracy of the present method is verified by comparison with experimental data.The slope can affect both the mean and fluctuating wind flow fields around the 3D hill,especially on the hilltop and the leeward side,where a critical slope of 25°can be observed.The fluctuating wind speeds at the tops of steep hills(with slope angles beyond 25°)decrease with increasing slope,while the opposite phenomenon occurs on gentle hills.With increasing slope,the energy of the high-speed descending airflow is enhanced and pushes the separated flow closer to the hill surface,resulting in increased wind speed near the wall boundary on the leeward side and inhibiting the development of turbulence.The vortex shedding trajectory in the wake region becomes wider and longer,suppressing the growth of the mean wind near the wall boundary and enhancing the turbulence intensity.
文摘This paper based on Reynolds-averaged Navier-Stokes equations standard ?model [1];the surface pressure on the wind field around two adjacent high-rise buildings was numerically simulated with software Fluent. The results show that with the influence of adjacent high-rise building, numerical simulation is a good way to study the wind field around high-rise building and the distribution of wind pressure on building’ surface. The pressures on the windward surface are positive with the maximum at 2/3 H height and have lower values on the top and bottom. The pressures on the leeward surface and two sides were negative. Due to the serious flow separation at the corner of building’s windward, the wind field has a high turbulent kinetic energy.
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.
文摘基于4个台风过程中的长时间序列风速、风方向观测数据,分析研究了近地台风的湍流积分尺度和脉动风速谱等脉动特性。介绍了湍流积分尺度的几种常见的计算方法,基于实测台风数据,分析研究了台风过程中湍流积分尺度的变化以及不同计算方法的稳定性。根据实测数据计算了纵向脉动风速谱,并与Von-Karm an谱、Davenport谱、S im iu谱和Harris谱等经验谱进行了比较,给出了最适合描述台风纵向脉动风速谱的经验谱。还计算了横向脉动风速功率谱,并与基于各向同性湍流理论推导出的水平横向脉动风速谱进行了对比。
