scholarly journals Comparison of the Blade Element Momentum Theory with Computational Fluid Dynamics for Wind Turbine Simulations in Turbulent Inflow

2018 ◽  
Vol 8 (12) ◽  
pp. 2513 ◽  
Author(s):  
Sebastian Ehrich ◽  
Carl Schwarz ◽  
Hamid Rahimi ◽  
Bernhard Stoevesandt ◽  
Joachim Peinke
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Standard Deviation ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Wind Fields ◽  
Turbulent Inflow ◽  
Power Spectral ◽  
Fatigue Loads ◽  
Blade Element

In this work three different numerical methods are used to simulate a multi-megawatt class class wind turbine under turbulent inflow conditions. These methods are a blade resolved Computational Fluid Dynamics (CFD) simulation, an actuator line based CFD simulation and a Blade Element Momentum (BEM) approach with wind fields extracted from an empty CFD domain. For all three methods sectional and integral forces are investigated in terms of mean, standard deviation, power spectral density and fatigue loads. It is shown that the average axial and tangential forces are very similar in the mid span, but differ a lot near the root and tip, which is connected with smaller values for thrust and torque. The standard deviations in the sectional forces due to the turbulent wind fields are much higher almost everywhere for BEM than for the other two methods which leads to higher standard deviations in integral forces. The difference in the power spectral densities of sectional forces of all three methods depends highly on the radial position. However, the integral densities are in good agreement in the low frequency range for all methods. It is shown that the differences in the standard deviation between BEM and the CFD methods mainly stem from this part of the spectrum. Strong deviations are observed from 1.5 Hz onward. The fatigue loads of torque for the CFD based methods differ by only 0.4%, but BEM leads to a difference of up to 16%. For the thrust the BEM simulation results deviate by even 29% and the actuator line by 7% from the blade resolved case. An indication for a linear relation between standard deviation and fatigue loads for sectional as well as integral quantities is found.

Two-Dimensional Computational Fluid Dynamics Study on the Performance of Twin Vertical Axis Wind Turbine With Deflector

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Yichen Jiang ◽  
Peidong Zhao ◽  
Li Zou ◽  
Zhi Zong ◽  
Kun Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Energy Utilization ◽  
Offshore Wind ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Local Flow

Abstract The offshore wind industry is undergoing a rapid development due to its advantage over the onshore wind farm. The vertical axis wind turbine (VAWT) is deemed to be potential in offshore wind energy utilization. A design of the offshore vertical axis wind turbine with a deflector is proposed and studied in this paper. Two-dimensional computational fluid dynamics (CFD) simulation is employed to investigate the aerodynamic performance of wind turbine. An effective method of obtaining the blade’s angle of attack (AoA) is introduced in CFD simulation to help analyze the blade aerodynamic torque variation. The numerical simulations are validated against the measured torque and wake velocity, and the results show a good agreement with the experiment. It is found that the blade instantaneous torque is correlated with the local AoA. Among the three deflector configurations, the front deflector leads to favorable local flow for the blade, which is responsible for the improved performance.

scholarly journals Performance Prediction and Validation of a Small-Capacity Twisted Savonius Wind Turbine

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1721 ◽  
Author(s):  
Hyeonmu Jang ◽  
Insu Paek ◽  
Seungjoo Kim ◽  
Deockjin Jeong
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Performance Test ◽  
Cfd Simulation ◽  
Power Production ◽  
Maximum Power ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Simulation Results

In this study, an off-grid–type small wind turbine for street lighting was designed and analyzed. Its performance was predicted using a computational fluid dynamics model. The proposed wind turbine has two blades with a radius of 0.29 m and a height of 1.30 m. Ansys Fluent, a commercial computational fluid dynamics solver, was used to predict the performance, and the k-omega SST model was used as the turbulence model. The simulation result revealed a tip-speed ratio of 0.54 with a maximum power coefficient, or an aerodynamic rotor efficiency of 0.17. A wind turbine was installed at a measurement site to validate the simulation, and a performance test was used to measure the power production. To compare the simulation results obtained from the CFD simulation with the measured electrical power performance, the efficiencies of the generator and the controller were measured using a motor-generator testbed. Also, the control strategy of the controller was found from the field test and applied to the simulation results. Comparing the results of the numerical simulation with the experiment, the maximum power-production error at the same wind speed was found to be 4.32%.

scholarly journals Comparison of Computational Fluid Dynamics and Experimental Power Output of a Micro Horizontal-Axis Wind Turbine

2017 ◽  
Vol 7 (2 (S)) ◽  
pp. 11
Author(s):  
Sanjay Nikhade ◽  
Suhas Kongre ◽  
S. B. Thakre ◽  
S. S. Khandare
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Power Performance ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Cfd

This paper presents a combined experimental and Computational Fluid Dynamics (CFD) simulation of Micro wind Turbine with 2.28 meters rotor Diameter is performed using the FLUENT 16.2 WORKBENCH. A Micro Horizontal Axis Three Blade Wind Turbine was designed, developed and tested for power performance on new airfoil AFN2016 Designed. The three blades were fabricated from glass fiber with a rotor swept area of 3.14 sq.m for the 1-meter length of the blade and angle of attack experimentally determined to be 5º.The blade is designed for tip speed ratio (TSR) of 7. The power out measured for wind speed from 3.0m/s to 9.0 m/s. The comparison of the CFD and experimental results on the relationship between the power obtained and the wind speed of the wind turbine at the wind from 3-9 m/s. It can be clearly seen that the experimental data match quite well again with the numerical analysis and they both demonstrated that the power of wind turbine increasing with wind speed increases.

scholarly journals Wind turbine load dynamics in the context of turbulence intermittency

2019 ◽  
Author(s):  
Carl Michael Schwarz ◽  
Sebastian Ehrich ◽  
Joachim Peinke
Keyword(s):  
Wind Turbine ◽  
Design Guidelines ◽  
Spatial Correlations ◽  
Wind Fields ◽  
Wind Structure ◽  
Turbulence Intermittency ◽  
Velocity Increments ◽  
Fatigue Loads ◽  
Non Gaussian ◽  
Blade Element

Abstract. The importance of a high order statistical feature of wind, which is neglected in common wind models, is investigated: Non-Gaussian distributed wind velocity increments related to the intermittency of turbulence and their impact on wind turbines dynamics and fatigue loads are in the focus. Two types of synthetic wind fields obtained from a Continuous-Time-Random Walk model are compared and fed to a common Blade-Element/Momentum theory based aero-servo-elastic wind turbine model. It is discussed why and how the effect of the non-Gaussian increment statistics has to be isolated. This is achieved by assuring that both types feature equivalent probability density functions, spectral properties and coherence, which makes them indistinguishable based on wind characterizations of common design guidelines. Due to limitations in the wind field genesis idealized spatial correlations are considered. Three examples with idealized, differently sized wind structures are presented. A comparison between the resulting wind turbine loads is made. For the largest wind structure sizes differences in the fatigue loads between intermittent and Gaussian are observed. These are potentially relevant in a wind turbine certification context. Subsequently, the dependency of this intermittency effect on the field's spatial variation is discussed. Towards very small structured fields the effect vanishes.

scholarly journals Computational Fluid Dynamics Simulation to Predict the Airflow and Turbulence in a Wind Farm in Open Complex Terrain

Proceedings ◽  
2020 ◽  
Vol 63 (1) ◽  
pp. 33
Author(s):  
Amahjour Narjisse ◽  
Abdellatif Khamlichi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Wind Farm ◽  
Cfd Simulation ◽  
Dynamics Simulation ◽  
Height Distribution ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
Neutral Conditions

The performance of a wind turbine depends on the characteristics of the airflow as well as the conditions of the atmospheric boundary layer (ABL). To evaluate accurately the amount of wind energy, it is required to have the exact height distribution of wind speed for the considered implementation site of a wind turbine. In this paper, computational fluid dynamics (CFD) simulation predictions provided by the standard k-ε turbulence model under neutral conditions were examined. The objective is to investigate the influence of hill slopes in the microscale wind farm on the airflow velocity to optimize the location of wind turbines. The results were validated by RUSHIL wind tunnel data and were compared with flat terrain.

The Application of Computational Fluid Dynamics for Installing the Roof-Mounted Wind Turbine

2012 ◽  
Author(s):  
Lu Lu ◽  
Xiuling Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Cfd Modeling ◽  
Final Decision ◽  
Output Curve ◽  
Vertical Axis Wind Turbine ◽  
Wind Fields ◽  
Visualization Technology

Purdue University Calumet (PUC) was planning to install a Vertical Axis Wind Turbine (VAWT) on the roof of Student Union and Library (SUL) building, an academic building on campus, for teaching and research purposes. While several potential sites have been identified as feasible, computational fluid dynamics (CFD) modeling and Virtual Reality (VR) visualization technology have been coupled to assist in assessing the optimal location for sitting the wind turbine. 3-D wind fields were constructed which take into account the neighboring building effects to the flow fields. Wind speeds, turbulent intensity, and aesthetic look are some of the factors used to make the final decision. After the installation, estimated power generation was calculated based on the wind turbine power output curve and statistical analysis of measured wind data.

scholarly journals Computational Fluid Dynamics (CFD) Simulation on Mixing in T-Shaped Micromixer

2020 ◽  
Vol 932 ◽  
pp. 012006
Author(s):  
S N A Ahmad Termizi ◽  
C Y Khor ◽  
M A M Nawi ◽  
Nurlela Ahmad ◽  
Muhammad Ikman Ishak ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Computational Fluid Dynamics Cfd
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