Compensation of Bias in Lidar Wind Resource Assessment

2008 ◽  
Vol 32 (5) ◽  
pp. 415-432 ◽  
Author(s):  
P J M Clive
Keyword(s):  
Remote Sensing ◽  
Wind Speed ◽  
Wind Direction ◽  
Wind Shear ◽  
Volume Averaging ◽  
Average Wind Speed ◽  
Probe Length ◽  
The Impact ◽  
Power Curves ◽  
The Relationship

A number of vector and volume averaging considerations arise in relation to remote sensing, and in particular, Lidar. 1) Remote sensing devices obtain vector averages. The magnitude of a vector average is less than or equal to the scalar average obtained over the same period. The use of Lidars in wind power applications has introduced practices entailing the estimation of scalar average point quantities by the measurement of vector averages over volumes and vice versa. The relationship between vector and scalar averages, and the relationship between volume and point measurements, must therefore both be understood. It is found that their ratio depends upon wind direction variability according to a Bessel function of the standard deviation of the wind direction during the averaging interval. The impact of wind direction variability on power production is also explored. 2) The finite probe length of remote sensing devices incurs a volume averaging bias if wind shear is non-linear. The sensitivity of the devices to signals from a range of heights produces volume averages representing wind speeds within that range. If the wind shear is described by a logarithmic wind profile the apparent height, at which the average wind speed occurs, is found to depend on simple geometrical arguments concerning configuration height and probe length independent of the degree of wind shear. Similar arguments are applied to determine the ideal height across the rotor at which to acquire wind speed data for power curves. 3) The common restriction of the locus of points at which radial velocity measurements are made to the circumference of a horizontally oriented disc at a particular height is seen to introduce ambiguity into results when dealing with wind vector fields which are not uniform.

scholarly journals Analysis of wind impact on emission of selected exhaust compounds in jet engines of a business jet aircraft in cruise phase

2018 ◽  
Vol 173 (2) ◽  
pp. 55-60
Author(s):  
Małgorzata PAWLAK ◽  
Andrzej MAJKA ◽  
Michał KUŹNIAR ◽  
Jowita PAWLUCZY
Keyword(s):  
Wind Speed ◽  
Fuel Consumption ◽  
Wind Direction ◽  
Adverse Impact ◽  
Air Transport ◽  
Jet Engines ◽  
Business Jet ◽  
Condi Tions ◽  
Harmful Substances ◽  
The Impact

Among the most important problems currently faced by air transport, we can distinguish the adverse impact of aircrafts on the natu-ral environment, as well as the rising costs of transport. One of the possibilities to improve this situation is better adjustment of aircraft characteristics to the performed transport tasks, taking into account all the requirements and limitations that exist in air traffic and the adverse impact of air transport on the natural environment. It is reflected in the research tasks conducted under the SESAR program. The aspiration to minimize the adverse impact of aircrafts on the environment is executed, among others, through determining such trajectories that are characterized by minimal fuel consumption or minimal emission of harmful substances in the engines exhausts. These goals are corresponding with the research conducted and described in the paper. The main aim of the work was to analyse the impact of wind speed and direction on the emission of harmful substances of a jet aircraft performing a flight on a given route. For research purposes, the route between two Polish cities Gdansk and Rzeszow was considered. The distance between the two airports was divided into sections for which wind direction and strength were determined (read from the windy.com website). Next, the aircraft per-formance was determined and the fuel consumption and the amount of harmful compounds (CO2, NOx, CO and HC), emitted in the en-gines exhausts were determined for the route from Gdansk to Rzeszow (under favourable wind conditions) and on the return route – from Rzeszow to Gdansk (under unfavourable wind conditions). For comparative purposes, emission of these substances for windless condi-tions was also determined. The results are presented in tables and depicted in the graph, as well as discussed in the conclusions of the paper.

scholarly journals Numerical Simulation of the Aeroelastic Response of Wind Turbines in Typhoons Based on the Mesoscale WRF Model

2019 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Long Wang ◽  
Cheng Chen ◽  
Tongguang Wang ◽  
Weibin Wang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Direction ◽  
Flow Direction ◽  
Wrf Model ◽  
Normal Operation ◽  
Average Wind Speed ◽  
Aeroelastic Response ◽  
Response Characteristics ◽  
Wind Speeds

A new simulation method for the aeroelastic response of wind turbines under typhoons is proposed. The mesoscale Weather Research and Forecasting (WRF) model was used to simulate a typhoon’s average wind speed field. The measured power spectrum and inverse Fourier transform method were coupled to simulate the pulsating wind speed field. Based on the modal method and beam theory, the wind turbine model was constructed, and the GH-BLADED commercial software package was used to calculate the aerodynamic load and aeroelastic response. The proposed method was applied to assess aeroelastic response characteristics of a commercial 6 MW offshore wind turbine under different wind speeds and direction variation patterns for the case study of typhoon Hagupit (2008), with a maximal wind speed of 230 km/h. The simulation results show that the typhoon’s average wind speed field and turbulence characteristics simulated by the proposed method are in good agreement with the measured values: Their difference in the main flow direction is only 1.7%. The scope of the wind turbine blade in the typhoon is significantly larger than under normal wind, while that under normal operation is higher than that under shutdown, even at low wind speeds. In addition, an abrupt change in wind direction has a significant impact on wind turbine response characteristics. Under normal operation, a sharp variation of the wind direction by 90 degrees in 6 s increases the wind turbine (WT) vibration scope by 27.9% in comparison with the case of permanent wind direction. In particular, the maximum deflection of the wind tower tip in the incoming flow direction reaches 28.4 m, which significantly exceeds the design standard safety threshold.

scholarly journals Characteristics and the Potential Influence of Fugitive PM10 Emissions from Enclosed Storage Yards in Iron and Steel Plant

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 833
Author(s):  
Zijie Lin ◽  
Fujiang Wang ◽  
Tao Ji ◽  
Baolong Ma ◽  
Linyan Xu ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Discharge Rate ◽  
Particle Emission ◽  
Steel Plant ◽  
Fugitive Emission ◽  
Iron And Steel ◽  
Emission Estimation ◽  
The Impact ◽  
Pm10 Emissions

Fugitive particle emission of enclosed storage yards in iron and steel plant is a complicated and multivariable problem, which will have negative impacts on the environment and economy. Researchers have discussed methodologies of emission estimation in open storage yards, but rarely focused on enclosed ones. However, enclosed storage yards are commonly adopted in most industries in China. This paper links onsite observation and computational fluid dynamics (CFD) to estimate the impact of fugitive PM10 emissions from enclosed storage yards on the open air. By collecting and analyzing PM10 samples at three sites inside the yard and one site outside, The result shows that PM10 concentration is in the range of 7.3 ± 1.5~13.4 ± 4.2 mg/m3, which is extremely high in an enclosed storage yard, and significantly influences workers’ health inside and outside atmospheric aerosols. The CFD model simulation is conducted by considering particle deposition, particle emission sources of shovel loader and road dust emission, as well as different wind direction and wind speed. The result shows that PM10 discharge rate from the enclosed area to open-air is significantly influenced by wind velocity and direction, e.g., the result of northwest wind with wind speed in 12.7 m/s is eight times higher than wind speed in 2.5 m/s with the same wind direction, and are 47 and 62 times higher than the east and west wind direction with the same wind speed in 12.7 m/s, respectively. In this case, the PM10 discharge rate is about 131.7 ton/year, which contains about 38~55 ton/year iron-relating particles. This will directly contribute PM10 to open-air and may produce secondary aerosols, due to heterogeneous catalytic reaction. This work identifies the important contribution of fugitive emissions and provides an approach for fugitive emission estimation of industries to the surrounding air. The results provide a reference for material yard zoning and fugitive emission control from minimizing influence from the meteorological condition and reducing source discharge inside.

Bridge Design Basic Wind Speed Based on the Joint Distribution of Wind Speed and Direction

2011 ◽  
Vol 90-93 ◽  
pp. 805-812 ◽  
Author(s):  
Zheng Wei Ye ◽  
Yi Qiang Xiang
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Joint Distribution ◽  
Probability Model ◽  
Model Fitting ◽  
Frequency Function ◽  
Actual Distribution ◽  
Extreme Type ◽  
Sampling Intervals ◽  
The Impact

Based on the method of separation of wind speed and direction variable, considering the wind direction frequency function, ascending order to calculate the probability of the actual distribution of the sample, extreme type Ⅰ (Gumbel) and three parameters of extreme type Ⅱ (Frechet) and extreme type Ⅲ (Weibull) probability distribution to fit the sample, this paper has analyzed the weather station observations of 34 consecutive years of the joint distribution of wind speed and direction near to a huge bridge, gained the basic design wind speed in different directions, comparatively analyzed the impact of the sampling interval of change on the basic wind speed as well. The results shows: wind speed in different directions at the same location or different sampling intervals samples of the wind speed sample may be subject to different types of extreme value distribution, should separately fitting; different wind direction frequency of extreme wind speed occurrence and the basic wind speed there are certain differences, taking into account the joint distribution of wind speed and direction is necessary to determine the design basic wind speed of the bridge, and will be conservative without considering the joint distribution; for the same sample wind speed matrix, the shorter the sampling intervals, the optimal distribution of the higher probability model fitting precision, the smaller the basic wind speed, the more economic and reasonable the results.

Influence of Atmospheric Stability on Wind Turbine Power Performance Curves

2006 ◽  
Vol 128 (4) ◽  
pp. 531-538 ◽  
Author(s):  
Jonathon Sumner ◽  
Christian Masson
Keyword(s):  
Wind Speed ◽  
Wind Farm ◽  
Similarity Theory ◽  
Atmospheric Stability ◽  
Performance Testing ◽  
System Of Nonlinear Equations ◽  
Power Performance ◽  
Turbine Efficiency ◽  
The Impact ◽  
Power Curves

The impact of atmospheric stability on vertical wind profiles is reviewed and the implications for power performance testing and site evaluation are investigated. Velocity, temperature, and turbulence intensity profiles are generated using the model presented by Sumner and Masson. This technique couples Monin-Obukhov similarity theory with an algebraic turbulence equation derived from the k-ϵ turbulence model to resolve atmospheric parameters u*, L, T*, and z0. The resulting system of nonlinear equations is solved with a Newton-Raphson algorithm. The disk-averaged wind speed u¯disk is then evaluated by numerically integrating the resulting velocity profile over the swept area of the rotor. Power performance and annual energy production (AEP) calculations for a Vestas Windane-34 turbine from a wind farm in Delabole, England, are carried out using both disk-averaged and hub height wind speeds. Although the power curves generated with each wind speed definition show only slight differences, there is an appreciable impact on the measured maximum turbine efficiency. Furthermore, when the Weibull parameters for the site are recalculated using u¯disk, the AEP prediction using the modified parameters falls by nearly 5% compared to current methods. The IEC assumption that the hub height wind speed can be considered representative tends to underestimate maximum turbine efficiency. When this assumption is further applied to energy predictions, it appears that the tendency is to overestimate the site potential.

Removing the impact of wind direction on remote sensing of sea surface salinity

2006 ◽  
Vol 51 (11) ◽  
pp. 1368-1373 ◽  
Author(s):  
Xiaobin Yin ◽  
Yuguang Liu ◽  
Hande Zhang
Keyword(s):  
Remote Sensing ◽  
Wind Direction ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
The Impact

scholarly journals The Large-eddy Observatory Voitsumra Experiment 2019 (LOVE19) with high-resolution, spatially-distributed observations of air temperature, wind speed, and wind direction from fiber-optic distributed sensing, towers, and ground-based remote sensing

2021 ◽  
Author(s):  
Karl Lapo ◽  
Anita Freundorfer ◽  
Antonia Fritz ◽  
Johann Schneider ◽  
Johannes Olesch ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Wind Speed ◽  
Air Temperature ◽  
Wind Direction ◽  
Fiber Optic ◽  
Layer Structure ◽  
Distributed Sensing ◽  
Near Surface ◽  
Large Eddy

Abstract. The weak-wind Stable Boundary Layer (wwSBL) is poorly described by theory and breaks basic assumptions necessary for observations of turbulence. Understanding the wwSBL requires distributed observations capable of separating between submeso and turbulent scales. To this end, we present the Large Eddy Observatory, Voitsumra Experiment 2019 (LOVE19) which featured 1350 m of fiber optic distributed sensing (FODS) of air temperature and wind speed, as well as an experimental wind direction method, at scales as fine as 1 s and 0.127 m in addition to a suite of point observations of turbulence and ground-based remote sensing. Additionally, flights with a fiber optic cable attached to a tethered balloon provide an unprecedented detailed view of the boundary layer structure with a resolution of 0.254 m and 10 s between 1–200 m height. Two examples are provided demonstrating the unique capabilities of the LOVE19 data for examining boundary layer processes: 1) FODS observations between 1m and ~200 m height during a period of gravity waves propagating across the entire boundary layer and 2) tracking a near-surface, transient submeso structure that causes an intermittent burst of turbulence. All data can be accessed at Zenodo through the DOI https://doi.org/10.5281/zenodo.4312976 (Lapo et al., 2020a).

scholarly journals A Micro-Scale Cyclone-Wind Turbine for Rooftop Ventilator

2018 ◽  
Vol 11 (2) ◽  
pp. 614
Author(s):  
Unggul Wibawa ◽  
Akhmad Frandicahya Permadi ◽  
Rini Nur Hasanah
Keyword(s):  
Wind Speed ◽  
Power System ◽  
Micro Scale ◽  
Battery Power ◽  
Speed Range ◽  
System Output ◽  
System Data ◽  
Wind Power System ◽  
The Impact ◽  
The Relationship

This paper analyzes the model of a cyclone-turbine for a micro-scale wind-power system being motivated by an idea to harvest the abandoned energy from rooftop ventilators. The system under consideration has been equipped with a battery to form a wind-battery power system. Data obtained from a wind site observation have been used to calculate the potentially generated power and efficiency, as well as the mechanical and electrical designs to extract the energy. The design has been explored to obtain the best efficiency of the cyclone-turbine model. The impact of wind-speed variation on the resulted system output has been investigated during the charging process of battery. The conclusion emphasizes the relationship between the output power and the range values of the resulted current and voltage, as well as the optimum wind speed-range of the cyclone-turbine operation.

scholarly journals A New Remote Sensing Index for Assessing Spatial Heterogeneity in Urban Ecoenvironmental-Quality-Associated Road Networks

Land ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Xincheng Zheng ◽  
Zeyao Zou ◽  
Chongmin Xu ◽  
Sen Lin ◽  
Zhilong Wu ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Surface ◽  
Road Network ◽  
Vegetation Index ◽  
Road Networks ◽  
Bare Soil ◽  
Coupling Mechanism ◽  
Ecological Index ◽  
The Impact ◽  
The Relationship

Although many prior efforts found that road networks significantly affect landscape fragmentation, the spatially heterogeneous effects of road networks on urban ecoenvironments remain poorly understood. A new remote-sensing-based ecological index (RSEI) is proposed to calculate the ecoenvironmental quality, and a local model (geographically weighted regression, GWR) was applied to explore the spatial variations in the relationship between kernel density of roads (KDR) and ecoenvironmental quality and understand the coupling mechanism of road networks and ecoenvironments. The average effect of KDR on the variables of normalized difference vegetation index (NDVI), land surface moisture (LSM), and RSEI was negative, while it was positively associated with the soil index (SI), normalized differential build-up and bare soil index (NDBSI), index-based built-up index (IBI), and land surface temperature (LST). This study shows that rivers and the landscape pattern along rivers exacerbate the impact of road networks on urban ecoenvironments. Moreover, spatial variation in the relationship between road network and ecoenvironment is mainly controlled by the relationship of the road network with vegetation and bare soil. This research can help in better understanding the diversified relationships between road networks and ecoenvironments and offers guidance for urban planners to avoid or mitigate the negative impacts of roads on urban ecoenvironments.

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