An Environmental Wind Tunnel Laboratory of SP

This paper briefs the background and process of setting-up andupdating of Environmental Wind Tunnel Laboratory of State Power Corporation,details the environmental wind tunnel, completed measuring instruments andequipment of the laboratory, and also describes the experimental projects thePower Environmental Protection Research Institute has completed, theexperiences gained and the services the Institute can provide in the future.[

Wind dynamic environment and wind-sand erosion and deposition processes on different surfaces along the Dunhuang–Golmud railway,China

The Dunhuang–Golmud railway passes through different deserts in arid areas,especially drifting-sand desert and sandy-gravel Gobi.The near-surface wind environment and wind-sand transport process vary due to different external factors,such as topography,vegetation,and regional climate,resulting in evident spatial differences in surface erosion and deposition.Consequently,the measures for preventing wind-sand hazards will differ.However,the mechanism and control theory of sand damage remain poorly understood.In this study,we used meteorological observation,three-dimensional(3D)laser scanning,and grain-size analysis to compare and evaluate the spatial distribution of wind conditions,sand erosion and deposition patterns,and grain composition in the drifting-sand desert and sandy-gravel Gobi along the Dunhuang–Golmud railway in China.Results show that the annual mean wind speed,the frequency of sand-driving wind,and the drift potential of sandy-gravel Gobi are higher than those of drifting-sand desert,indicating a greater wind strength in the sandy-gravel Gobi,which exhibits spatial heterogeneity in wind conditions.The major sediment components in sandy-gravel Gobi are very fine sand,fine sand,and medium sand,and that in drifting-sand desert are very fine sand and fine sand.We found that the sediment in the sandy-gravel Gobi is coarser than that in the drifting-sand desert based on mean grain size and sediment component.The spatial distributions of sand erosion and deposition in the sandy-gravel Gobi and drifting-sand desert are consistent,with sand deposition mainly on the west side of the railway and sand erosion on the east side of the railway.The area of sand deposition in the drifting-sand desert accounts for 75.83%of the total area,with a mean deposition thickness of 0.032 m;while the area of sand deposition in the sandy-gravel Gobi accounts for 65.31%of the total area,with a mean deposition thickness of 0.028 m,indicating greater deposition amounts in the drifting-sand desert due to the presence of more fine sediment components.However,the sand deposition is more concentrated with a greater thickness on the embankment and track in the sandy-gravel Gobi and is dispersed with a uniform thickness in the drifting-sand desert.The sand deposition on the track of the sandy-gravel Gobi mainly comes from the east side of the railway.The results of this study are helpful in developing the preventive measures and determining appropriate selection and layout measures for sand control.

Wind and Snow Impacts on Urban Space Planning:A Multiphase Numerical Simulation

The wind and snow environment outside the planned space plays a key role in the comfort and safety of the human habitat in severe cold regions. Traditional studies of the external environment of human settlements, however, frequently overlook the combined impacts of wind and snow environments. Furthermore, in urban meteorological studies, it is impossible to accurately assess the wind and snow environment in specific areas or locations. In this study, a refined Computational Fluid Dynamics(CFD) multiphase flow numerical method was used to simulate a planning space's wind and snow environment. The study classified the Snowstorm Weather Grade(SWG) by incorporating the Snowstorm Weather Index(SWI) to generate calculation results of the wind environment and snow environment. In particular, 150 measurement points in the planning space were chosen for analysis and evaluation of their wind and snow environments. The results demonstrated that the SWI index can effectively correlate to the wind and snow environment calculation results. In addition, the graph of SWI showed that 55% of the measurement points had a moderate wind and snow grade SWI, which exceeds the average grade for the entire region. The practical application shows that the wind and snow environment assessment indexes and technical methods developed in this paper can be successfully applied to wind and snow environment studies in other cold cities.

Computational fluid dynamics evaluation of the effect of different city designs on the wind environment of a downwind natural heritage site

Disturbance in wind regime and sand erosion deposition balance may lead to burial and eventual vanishing of a site.This study conducted 3D computational fluid dynamics(CFD)simulations to evaluate the effect of a proposed city design on the wind environment of the Crescent Spring,a downwind natural heritage site located in Dunhuang,Northwestern China.Satellite terrain data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)Digital Elevation Model(DEM)were used to construct the solid surface model.Steady-state Reynolds Averaged Navier-Stokes equations(RANS)with shear stress transport(SST)k-ωturbulence model were then applied to solve the flow field problems.Land-use changes were modeled implicitly by dividing the underlying surface into different areas and by applying corresponding aerodynamic roughness lengths.Simulations were performed by using cases with different city areas and building heights.Results show that the selected model could capture the surface roughness changes and could adjust wind profile over a large area.Wind profiles varied over the greenfield to the north and over the Gobi land to the east of the spring.Therefore,different wind speed reduction effects were observed from various city construction scenarios.The current city design would lead to about 2 m/s of wind speed reduction at the downwind city edge and about 1 m/s of wind speed reduction at the north of the spring at 35-m height.Reducing the city height in the north greenfield area could efficiently eliminate the negative effects of wind spee.By contrast,restricting the city area worked better in the eastern Gobi area compared with other parts of the study area.Wind speed reduction in areas near the spring could be limited to 0.1 m/s by combining these two abatement strategies.The CFD method could be applied to simulate the wind environment affected by other land-use changes over a large terrain.

Wind regimes and associated sand dune types in the hinterland of the Badain Jaran Desert,China

Wind controls the formation and development of sand dunes.Therefore,understanding the wind regimes is necessary in sand dune research.In this study,we combined the wind data from 2017 to 2019 at four meteorological stations(Cherigele and Wuertabulage stations in the lake basins,and Yikeri and Sumujilin stations on the top of sand dunes)in the hinterland of the Badain Jaran Desert in China,with high resolution Google Earth images to analyze the correlation between the wind energy environments and dune morphology.The results of data analysis indicated that both the wind direction and sand drift intensity exhibited notable spatial and temporal variations.The highest level of wind activity was observed in spring.Northwesterly and northeasterly winds were the dominant in the Badain Jaran Desert.At the Cherigele,Wuertabulage,and Yikeri stations,the drift potential(DP)was below 200.00 vector units(VU).The wind energy environments in most areas could be classified as low-energy environments.The resultant drift direction differed at different stations and in different seasons,but the overall direction was mainly the southeast.The resultant drift potential(RDP)/DP ratio was greater than 0.30 in most parts of the study area,suggesting that the wind regimes mainly exhibited unimodal or bimodal characteristics.Differences between the thermodynamic properties and the unique landscape settings of lakes and sand dunes could alter the local circulation and intensify the complexity of the wind regimes.The wind regimes were weaker in the lake basins than on the top of sand dunes.Transverse dunes were the most dominant types of sand dunes in the study area,and the wind regimes at most stations were consistent with sand dune types.Wind was thus the main dynamic factor affecting the formation of sand dunes in the Badain Jaran Desert BJD.The results of this study are important for understanding the relationship between the wind regimes and aeolian landforms of the dune field in the deserts.

EFFECTS OF VERTICAL WIND SHEAR ON TROPICAL CYCLONE INTENSITY CHANGE

The effects of vertical wind shear on tropical cyclone(TC) intensity change are examined based on the TC data from the China Meteorological Administration and the NCEP reanalysis daily data from 2001 to 2006.First,the influence of wind shear between different vertical levels and averages in different horizontal areas are compared.The results indicate that the effect of wind shear between 200 and 850 hPa averaged within a 200-800 km annulus on TC intensity change is larger than any other calculated vertical wind shear.High-latitude and intense TCs tend to be less sensitive to the effects of VWS than low-latitude and weak TCs.TCs experience time lags between the imposition of the shear and the weakening in TC intensity.A vertical shear of 8-9 m/s(9-10 m/s) would weaken TC intensity within 60 h(48 h).A vertical shear greater than 10 m/s would weaken TC intensity within 6 h.Finally,a statistical TC intensity prediction scheme is developed by using partial least squares regression,which produces skillful intensity forecasts when potential predictors include factors related to the vertical wind shear.Analysis of the standardized regression coefficients further confirms the obtained statistical results.

Study on the Outdoor Wind Environment Simulation and Design Strategies of Rural Settlements in Cold Areas

To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper applies the method of numerical simulation to simulate the wind environment of some typical arrangement of building and courtyard in winter,and concludes the optimal building and courtyard arrangement types and strategies. It aims to provide some technical supports for improving the wind environment of rural settlements in cold regions.

Numerical Simulation Analysis and Ecological Evaluation on Wind Environment of Dwelling Groups in Severe Cold Regions

The wind environment around residential building groups is increasingly concerned,while the dwelling groups as the elementary unit of planning design,its quality of surrounding wind environment will directly affect people's life. This study based on the climatic conditions of severe cold regions,selects four dwellings groups with different openings scale and position as the research objects,and then simulates and analyzes the wind speed distribution characteristics of each pattern. Meanwhile,it extracts the wind speed values of one hundred points of each pattern and applies the coefficient of uniformity method to the ecological evaluation. It has been found that grouping pattern of buildings has a dramatic effect on the resulting airflow behavior. Configurations that contain a T-shaped central space with small opened side can effectively prevent and contain airflow in the site offer. The interactive influence between layout of dwelling groups and wind environment are explored,so as to provide basis for the planning design of dwelling groups.

Influence of Waterside Buildings’ Layout on Wind Environment and the Relation with Design Based on a Case Study of the She Kou Residential District

It is important to improve residential thermal comfort in the high dense cities,in which wind environment is crucial.Waterside buildings take an advantage of micro-hydrological-climate in summer that should be used to enhance residential thermal comfort especially in the subtropical region.In order to propose design approaches according to the outdoor thermal comfort of the waterside residential,a case study of Shenzhen She Kou res­idential district has been made.It focused on various factors that could have influence on wind environment for improving thermal comfort.Using wind velocity ratio(ΔRi)criterion,factors of building development volume,building direction and layout pattern,open space arrangement etc.have been broadly explored using FLUENT simulation.To planning parameters,the Floor Area Ratio(FAR)is significantly influence wind environment,the smaller FAR is better.To the vertical layout of the buildings,multi-storey layout and multi-storey&sub high-rise mixed layout would provide better wind environment.To the horizontal layout,the determinant is better than the peripheral.Other factors such as the buildings’direction towards the road,buildings’height,and open space setting,have influence on wind environment yet.In general,the more benefit of design layout for wind breezing,the better wind environment it could get.

Numerical simulation of wind flow fields around buildings using the lattice Boltzmann method

This paper presents the simulation results of the wind environment around a single high-rise building and that around two tall buildings in tandem arrangement by using the lattice Boltzmann method with an aim to understand the ventilation issues around high-rise buildings in an urban environment.We analyzed the velocity distribution around the buildings and performed numericl simulations to reveal the formation and evolution law of the complex vortex system around the high-rise buildings.Numerical simulation results manifest a periodicity phenamenon in the process of the vortex evolution.For the case of two high-rise buildings,wind velocity in the space between the two buildings is very small,which is nearly a silent regime.Wind velocity above the front building is relatively larger and the maximum wind velocity is approximately 2.5 times the incoming wind velocity.The numerical results can be used in layout planning of high-rise residential buildings to create better environment for ventilation purpose in an urban area.

Review of Research Advances in CFD Techniques for the Simulation of Urban Wind Environments

Computational fluid dynamics(CFD)has become the main method for the prediction of the properties of the external wind environment in cities and other urban contexts.A review is presented of the existing literature in terms of boundary conditions,building models,computational domains,computational grids,and turbulence models.Some specific issues,such as the accuracy/computational cost ratio and the exploitation of existing empirical correlations,are also examined.

A Computational Model for Pedestrian Level Wind Environment Around Tall Buildings

A computational model has been developed for the simulation of pedestrian level wind environment around tall buildings by coupling the numerical simulation of the full scale site and meteorological station materials. In the first step, the hybrid/mixed finite element method is employed to solve the two dimensional Navier Stokes equation for the flow field around tall buildings, in view of the influence of fluctuating wind, the flow field is revised with the effective wind velocity. The velocity ratio is defined in order to relate numerical wind velocity to oncoming reference wind velocity. In the second step, the frequency occurred discomfort wind velocity as a suitable criterion is calculated by use of the coupling between the numerical wind velocity and the wind velocity at the nearest meteorological station. The prediction accuracy of the wind environment simulation by use of the computation model will be discussed. Using the available wind data at the nearest meteorological station as well as the established criteria of wind discomfort, the frequency of wind discomfort can be predicted. A numerical example is given to illustrate the application of the proposed method.

Simulation and Optimization of Traditional Village Wind Environment under Epidemic Prevention and Control:Take Anziling Village of Handan as an example

In the context of epidemic prevention and control,villages are the weakest part of epidemic prevention and control.Traditional villages,as representatives of villages,are often far away from cities,and medical conditions are relatively backward.Based on this background,epidemic prevention and control are particularly important.The quality of the environment is positively related to the spread of the virus.This article wanted to use CFD technology to simulate the wind environment of the traditional village street space,so as to propose measures to optimize the wind environment of the traditional village street space,and provide references for the future planning of village layout.

A Case Study on Optimization of Urban Design Base on Wind Environment Simulation

Wind environment simulation of a commercial district in Baise city of Guangxi Province, China, is carried out in the design phase. The results are analyzed and based on the evaluation standard for greening building of China. The simulation method is discussed in detail, and some suggestions for wind environment optimization are put forward, which might be helpful for similar research.

Climatic and Environmental Characteristics of Beijing Based on Rapid Processing Technology of Urban Meteorological Big Data

The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environment.With the help of computer programming and software processing,big data crawling,integration,extraction and multi-dimensional information fusion can be realized quickly and effectively,so as to obtain the data set needed for research and realize the target of visualization.Through big data analysis of wind environment,thermal environment and total atmospheric suspended particulate pollutants in Beijing area,it was found that the average wind speed in Beijing area decreased signifi cantly in recent 40 years,while the surface temperature increased signifi cantly;urban heat island effect was signifi cant,and the phenomenon of atmospheric suspended particulate pollution was relatively common.The spatial distribution of the three climatic and environmental data was not balanced and had signifi cant regularity and correlation.Improving urban ventilation corridors and improving urban ventilation capacity is a feasible way to improve urban heat island effect and reduce urban climate issues such as atmospheric particulate pollution.

Landscape Visual Environment Impact Analysis of Wind Power Project in Plain Region--Case in One Wind Power Farm Project of Zhanjiang

The construction of wind power project is conducive to saving energy,reducing emissions and regulating energy structure. But it inevitably causes some impacts on the environment in the construction process. Because that the height of wind power generator generally exceeds 100 m,and visual range in plain region is farther,it is necessary to scientifically and rationally evaluate and analyze landscape visual environment impact of wind power generator in plain region. One wind power farm project of Zhanjiang is located in typical plain region of Guangdong coast. Referring to traditional analytic method of landscape visual impact and comparing with actual situation for the same kind of project in the region,results show that it is ＂ extremely sensitive＂ area at 0- 2. 5 km from wind power generator, ＂ very sensitive＂ area at 2. 5- 5. 0 km, ＂ sensitive＂ area at 5- 10 km, ＂generally sensitive＂ area at 10- 20 km,and non-sensitive area outside 20 km.

Characteristics of wind-sand transportation along railways in the eastern fringe of the Taklimakan Desert and sand control system

This paper focuses on the Korla-Ruoqiang desert railway line,utilizing ERAS(ERA5 is the fifth generation of ECMWF(European Centre for Medium-Range Weather Forecasts)atmospheric reanalysis global climate data)wind data to conduct a comprehensive analysis of the wind energy environment along the line in all aspects,reveals the characteristics of wind-sand transport,and puts forward the countermeasures to prevent and control wind-sand disasters.The results of the study indicate that:(1)the wind-sand along the line mainly occurs in the spring and summer seasons,and the dominant sand-moving directions are easterly(ENE,E and NNE)and northeasterly(NE).(2)The average annual sand-moving wind speed ranges from 5.80 m/s to 7.25 m/s,and the annual frequency of sand-moving ranges from 11.99%to 37.26%.(3)The annual sand drift potential(DP)along the line ranges from 69.20 VU to 607.24 VU,with three types of wind energy environments:low,medium and high.The resultant drift potential(RDP)ranges from 45.52 VU to 547.49 VU,and the wind variability index(RDP/DP)is between 0.54 and 0.90.(4)The average sand transport quantity along the line ranges from 2.92 m^(3)/m/a to 9.09 m3/m/a.Based on these results,we optimize the sand blocking,sand fixing and wind erosion prevention measures for different types of wind-sand environments,establish a scientific and efficient wind-sand protection and control system to solve the wind-sand problems and provide a scientific foundation for the prevention and control of wind-sand disasters along the line.

Optimal design of vegetation in residential district with numerical simulation and field experiment

Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment improvement in winter was investigated by carrying out field experiments in Heqingyuan residential area in Beijing,and after that,numerical simulation with SPOTE(simulation platform for outdoor thermal environment) experiments for outdoor thermal environment of vegetation was adopted for comparison.The conclusions were summarized as follows:1) By comparing the experimental data with simulation results,it could be concluded that the wind field simulated was consistent with the actual wind field,and the flow distribution impacted by vegetation could be accurately reflected;2) The wind velocity with vegetation was lower than that without vegetation,and the wind velocity was reduced by 46%;3) By adjusting arrangement and types of vegetation in the regions with excessively large wind velocity,the pedestrian-level wind velocity could be obviously improved through the simulation and comparison.

Wind environment around the setback building models

The irregular shape of buildings always tenders an enormous challenge to the designers.The wind velocity at the pedestrian level has a specific approach from a comfortable point of view.This investigation highlighted the characteristic of the pedestrian level wind velocity for distinct types of asymmetrical setback buildings.The passed study explored the pedestrian level effect for the axisymmetric models,while this study is based on the models that have symmetry about a single axis.This study investigates the pedestrian level flow fluctuation of setback models with single and double side setbacks at multiple levels.The double-side double setback buildings are efficient to reduce 28%-30%velocity in front of the building and 68%-70%velocity behind the building.Finally it suggests that the double side double setback building is efficient to maintain the velocity at the pedestrian level,roof level,and backside of the building.The setback building can easily control the frequency of fluctuating velocity at downstream flow for both along and across wind conditions.

STUDY ON THE WIND AND WAVE EXTREME PARAMETERS OF TONKIN GULF IN THE SOUTH CHINA SEA-THE APPLICATIONS OF LAGFD NUMERICAL MODELS

Based on the hindcast of the severest 75 tropical cyclones (hereafter is called TCs) which affected Tonkin Gulf in history, the present paper gives sea surface wind and wave extreme parameters at 38 points corresponding to (1/2)×(1/2)?grid in the Gulf. The research increases our understanding of the meteo-ocean conditions on the whole area and provides basic data for ocean environmental research and engineering design.