scholarly journals Wind turbine wake models' evaluation for different downstream locations

2021 ◽  
Vol 6 ◽  
pp. 40
Author(s):  
Panagiotis Triantafyllou ◽  
John K. Kaldellis
Keyword(s):  
Wind Speed ◽  
Research Work ◽  
Past Research ◽  
Wake Flow ◽  
Wake Effect ◽  
Calculation Results ◽  
Wind Park ◽  
Semi Empirical ◽  
Turbine Wake ◽  
Streamwise Distance

The land use limitations, especially for onshore applications, have led modern Wind Turbines (WTs) to be aggregated in wind parks under the scope of minimizing the necessary area required. Within this framework, the trustworthy prediction of the wind speed deficiency downstream the WTs' hub (known also as the “wake effect”) and the meticulous wind park micrositing are of uppermost importance for the optimized WTs siting across the available land area. In this context, substantial effort has been made by the academic and research community, contributing to the deployment of several analytical, numerical and semi-empirical wake models, attempting to estimate the wind speed values at different locations downstream a WT. The accuracy of several semi-empirical and analytical wake models, serving also as the basis for pertinent commercial software development, is investigated in the present work, by comparing their outcome with experimental data from a past research work that concerns the wake flow. The dimensionless streamwise distance (known also with the term “downstream distance”) from the WT's hub is used as benchmark in order to categorize and evaluate the calculation results. A dedicated comparison between the wind speed cases investigated is conducted, striving to properly assess the wake models' prediction accuracy. The notable findings obtained for the wake models examined designate the requirement for subsequent research to enlighten the wake effect dynamic behavior.

A REVIEW OF WIND TURBINE WAKE MODELS FOR WIND PARK OPTIMIZATION

2019 ◽  
Author(s):  
Antonio Neiva ◽  
Vanessa Guedes ◽  
Caio Leandro Suzano Massa ◽  
Daniel Davy Bello de Freitas
Keyword(s):  
Wind Turbine ◽  
Wind Park ◽  
Turbine Wake ◽  
Wind Turbine Wake

scholarly journals Analysis of Wind Turbine Aging through Operation Data Calibrated by LiDAR Measurement

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2319
Author(s):  
Hyun-Goo Kim ◽  
Jin-Young Kim
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Wind Turbine ◽  
Wind Farm ◽  
Free Stream ◽  
Turbine Blades ◽  
Wind Farms ◽  
Lidar Measurement ◽  
Wind Turbine Blades ◽  
Wake Effect

This study analyzed the performance decline of wind turbine with age using the SCADA (Supervisory Control And Data Acquisition) data and the short-term in situ LiDAR (Light Detection and Ranging) measurements taken at the Shinan wind farm located on the coast of Bigeumdo Island in the southwestern sea of South Korea. Existing methods have generally attempted to estimate performance aging through long-term trend analysis of a normalized capacity factor in which wind speed variability is calibrated. However, this study proposes a new method using SCADA data for wind farms whose total operation period is short (less than a decade). That is, the trend of power output deficit between predicted and actual power generation was analyzed in order to estimate performance aging, wherein a theoretically predicted level of power generation was calculated by substituting a free stream wind speed projecting to a wind turbine into its power curve. To calibrate a distorted wind speed measurement in a nacelle anemometer caused by the wake effect resulting from the rotation of wind-turbine blades and the shape of the nacelle, the free stream wind speed was measured using LiDAR remote sensing as the reference data; and the nacelle transfer function, which converts nacelle wind speed into free stream wind speed, was derived. A four-year analysis of the Shinan wind farm showed that the rate of performance aging of the wind turbines was estimated to be −0.52%p/year.

THE INVESTIGATION OF ELECTRONIC PROPERTIES AND MICROSCOPIC SECOND-ORDER NONLINEAR OPTICAL BEHAVIOR OF 1-SALICYLIDENE-3-THIO-SEMICARBAZONE

2007 ◽  
Vol 16 (01) ◽  
pp. 91-99 ◽  
Author(s):  
ASLI KARAKAS ◽  
HUSEYIN UNVER ◽  
AYHAN ELMALI
Keyword(s):  
Molecular Orbital ◽  
Electronic Transition ◽  
Nonlinear Optical ◽  
Dipole Moments ◽  
Empirical Method ◽  
Second Order ◽  
Nlo Properties ◽  
Calculation Results ◽  
Moller Plesset ◽  
Semi Empirical

To investigate the microscopic second-order nonlinear optical (NLO) behavior of the 1-salicylidene-3-thio-semicarbazone Schiff base compound, the electric dipole moments (μ), linear static polarizabilities (α) and first static hyperpolarizabilites (β) have been calculated using finite field second-order Møller-Plesset perturbation (FF MP2) theory. The ab-initio results on (hyper)polarizabilities show that the investigated molecule might have microscopic NLO properties with non-zero values. To understand the NLO behavior in the context of molecular orbital structure, we have also examined the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and the HOMO-LUMO gap in the same theoretical framework as the (hyper)polarizability calculations. In addition to the NLO properties, the electronic transition spectra have been computed using a semi-empirical method (ZINDO). ZINDO calculation results show that the electronic transition wavelengths have been estimated to be shorter than 400 nm.

scholarly journals Performance Enhancement of Proposed Namaacha Wind Farm by Minimising Losses Due to the Wake Effect: A Mozambican Case Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4291
Author(s):  
Paxis Marques João Roque ◽  
Shyama Pada Chowdhury ◽  
Zhongjie Huan
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Output ◽  
Wind Farm ◽  
Wind Farms ◽  
Operating Conditions ◽  
Wake Effect ◽  
Wind Generators ◽  
Wind Potential

District of Namaacha in Maputo Province of Mozambique presents a high wind potential, with an average wind speed of around 7.5 m/s and huge open fields that are favourable to the installation of wind farms. However, in order to make better use of the wind potential, it is necessary to evaluate the operating conditions of the turbines and guide the independent power producers (IPPs) on how to efficiently use wind power. The investigation of the wind farm operating conditions is justified by the fact that the implementation of wind power systems is quite expensive, and therefore, it is imperative to find alternatives to reduce power losses and improve energy production. Taking into account the power needs in Mozambique, this project applied hybrid optimisation of multiple energy resources (HOMER) to size the capacity of the wind farm and the number of turbines that guarantee an adequate supply of power. Moreover, considering the topographic conditions of the site and the operational parameters of the turbines, the system advisor model (SAM) was applied to evaluate the performance of the Vestas V82-1.65 horizontal axis turbines and the system’s power output as a result of the wake effect. For any wind farm, it is evident that wind turbines’ wake effects significantly reduce the performance of wind farms. The paper seeks to design and examine the proper layout for practical placements of wind generators. Firstly, a survey on the Namaacha’s electricity demand was carried out in order to obtain the district’s daily load profile required to size the wind farm’s capacity. Secondly, with the previous knowledge that the operation of wind farms is affected by wake losses, different wake effect models applied by SAM were examined and the Eddy–Viscosity model was selected to perform the analysis. Three distinct layouts result from SAM optimisation, and the best one is recommended for wind turbines installation for maximising wind to energy generation. Although it is understood that the wake effect occurs on any wind farm, it is observed that wake losses can be minimised through the proper design of the wind generators’ placement layout. Therefore, any wind farm project should, from its layout, examine the optimal wind farm arrangement, which will depend on the wind speed, wind direction, turbine hub height, and other topographical characteristics of the area. In that context, considering the topographic and climate features of Mozambique, the study brings novelty in the way wind farms should be placed in the district and wake losses minimised. The study is based on a real assumption that the project can be implemented in the district, and thus, considering the wind farm’s capacity, the district’s energy needs could be met. The optimal transversal and longitudinal distances between turbines recommended are 8Do and 10Do, respectively, arranged according to layout 1, with wake losses of about 1.7%, land utilisation of about 6.46 Km2, and power output estimated at 71.844 GWh per year.

scholarly journals Analysis on the influence of sinusoidal wind on the structure of pumping unit based on dynamics of solid-fluid interaction

2021 ◽  
Vol 69 (5) ◽  
pp. 165
Author(s):  
Zheng Liang ◽  
Luo-ming Zhao ◽  
Li-qin Tan
Keyword(s):  
Wind Speed ◽  
Wind Field ◽  
Research Work ◽  
Scientific Basis ◽  
Wind Load ◽  
Load Range ◽  
Pumping Unit ◽  
Stress And Deformation ◽  
Fluid Interaction ◽  
Field Area

China National Petroleum Corporation Dingbian oilfield is located in the wind field area of the beam pumping unit affected by the wind load, occurred several pumping unit bracket bending, beam fracturing, horsehead off and horsehead drop and other serious accidents, endanger the equipment and personnel safety. However, there is little research on the influence of beam pumping unit under wind load. Based on the dynamics of solid-fluid interaction theory and the standard k- turbulence model, this paper calculated the polished rod load range of the pumping unit according to the actual working condition of Dingbian oilfield, and established the CYJ10-4.2-53 numerical model of wind field. Under the sinusoidal variable wind speed conditions, the stress and deformation of the beam loader with different sizes of wind load on the beam loader were compared to those of the different sorts. The stress and deformation of the two different types of pumping unit were compared under the wind load. The results show that under the influence of wind load, the rig of the pumping unit bracket has a serious bending deformation, and the safety risk of the front end of the horsehead along the wind load is deformed. When the wind speed reaches 24.48m/s, the horsehead and barcket’s offset is the largest to the top dead point by the wind load, The minimum impact is affected by the wind load at the bottom dead center, The maximum offset of the horsehead and the bracket reached 8.5 mm and 2.16 mm. The research work of this paper provides a scientific basis for the improvement of safety structure for pumping unit in the wind field area.

Labview-Based Automatic Four-Axis Positioning Control Air Temperature and Wind Speed Detection Platform for Drying Oven

2013 ◽  
Vol 718-720 ◽  
pp. 1547-1553 ◽  
Author(s):  
Neng Sheng Bao ◽  
Shi Liang Fei ◽  
Xue Jia Huang ◽  
Tie Quan Liu ◽  
Jin Huang
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Software Design ◽  
Research Work ◽  
Three Dimensional ◽  
Theoretical Research ◽  
Positioning Control ◽  
Processing Data ◽  
Cartesian Coordinate ◽  
Data Acquisition And Processing

The design of domestic drying oven lacked theoretical basis and methods, especially a tool supporting experiments and verifying the results of theoretical research. This paper developed a platform, which can be used to automatically detect multi-point air temperature and wind speed from drying oven nozzle of printing and coating machines. The hardware design of platform achieves a four-axis positioning function by adopt a three-dimensional Cartesian coordinate robot and an additional servo motor. The LabVIEW-based software design of platform achieves many functions, including multi-axis positioning control, data acquisition and processing, data interface and operation interface. This platform contributes to research work for drying oven.

scholarly journals A Review on Turbine Trailing Edge Flow

2020 ◽  
Vol 5 (2) ◽  
pp. 10
Author(s):  
Claus Sieverding ◽  
Marcello Manna
Keyword(s):  
Vortex Shedding ◽  
Point Of View ◽  
Wake Flow ◽  
Energy Separation ◽  
Trailing Edge ◽  
Time Resolved ◽  
Unsteady Wake ◽  
Aerodynamic Parameters ◽  
Unsteady Wake Flow ◽  
Turbine Wake

The paper presents a state-of-the-art review of turbine trailing edge flows, both from an experimental and numerical point of view. With the help of old and recent high-resolution time resolved data, the main advances in the understanding of the essential features of the unsteady wake flow are collected and homogenized. Attention is paid to the energy separation phenomenon occurring in turbine wakes, as well as to the effects of the aerodynamic parameters chiefly influencing the features of the vortex shedding. Achievements in terms of unsteady numerical simulations of turbine wake flow characterized by vigorous vortex shedding are also reviewed. Whenever possible the outcome of a detailed code-to-code and code-to-experiments validation process is presented and discussed, on account of the adopted numerical method and turbulence closure.

scholarly journals Design and analysis of wind pump for wind conditions in Pakistan

2019 ◽  
Vol 11 (9) ◽  
pp. 168781401988040 ◽  
Author(s):  
Tauseef Aized ◽  
Syed Muhammad Sohail Rehman ◽  
Sajid Kamran ◽  
Ali Hussain Kazim ◽  
Syed Ubaid ur Rehman
Keyword(s):  
Wind Speed ◽  
Power Output ◽  
Water Discharge ◽  
Research Work ◽  
Simulation Models ◽  
Energy Deficit ◽  
Ansys Fluent ◽  
Pump System ◽  
Wind Speed Data ◽  
Water Pumping

The unique thing about this research work is that it is the first comprehensive study out of all its kinds in Pakistan. Pakistan is an agricultural country and faces dearth of water resources availability for crops. This research work is very inevitable because it fulfils the water needs and also helps to minimize the energy deficit. This research article represents the means of wind speed data collection, design of wind-driven water pumping system and analysis of the design under different wind conditions in Pakistan. Wind speed data for province Punjab and Sindh are collected from Global Wind Atlas, Pakistan Meteorological Department and World Weather Online. First, design calculations have been made on the basis of analytical methods. Then proposed design is analysed using ANSYS Fluent Simulation models. Wind energy input, lift and drag on blades, rotor power output transmitted to the pump and water discharge from the pump have been calculated and verified from the simulation results. It has been shown that for any rotor size windmill produces maximum power output when angle between blade chord and axis of blade rotation is in the range of 23°–27°. Recommended height of windmill tower for 8–12 ft rotor diameter is 35–50 ft. Designed wind pump system can lift the ground water from 50 ft depth and discharge depends upon the size of windmill used. From the outcomes of the analysis, different designs having different power output and water pumping capacity have been proposed for different operating and wind conditions in the country.

Investigation of the Wake Effect From the Centrifugal Splitter Impeller Blade to the Vaned Diffuser

2012 ◽  
Author(s):  
Xuechen Li ◽  
Guang Xi ◽  
Jiang Hua ◽  
Wuqi Gong
Keyword(s):  
Flow Characteristics ◽  
Suction Side ◽  
Wake Flow ◽  
Centrifugal Impeller ◽  
Wake Effect ◽  
Impeller Blade ◽  
Vaned Diffuser ◽  
Side Pressure ◽  
Unsteady Wake ◽  
Impeller Outlet

In this paper, the unsteady wake effect from an unshrouded centrifugal impeller with splitter blades was numerically and experimentally investigated. The numerical simulated detail flow characteristics of two stations, respectively placed at the impeller outlet and the diffuser inlet, were compared with the measured data. The “jet-wake” flow pattern was observed at the exit of the impeller. And the investigation showed that the wake effect of the splitter was weaker that of the main blade. But both the main blade and the splitter blade wake could affect the diffuser performance at a range of whole-chord length and they provoked the pressure side profile pressure fluctuating intensely from 10% chord to 50% chord, while the suction side pressure varying rapidly at the range from 60% chord to 80% chord.

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