Wind tunnel test on mean wind forces and peak pressure acting on ellipsoidal nacelles of wind turbine

2021 ◽  
pp. 0309524X2110445
Author(s):  
Hiroshi Noda ◽  
Takeshi Ishihara
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Peak Pressure ◽  
Wind Tunnel Test ◽  
Load Case ◽  
Wind Force ◽  
Pressure Coefficients ◽  
Force Coefficients ◽  
Design Load ◽  
Mean Pressure

Mean wind forces and peak pressures acting on ellipsoidal nacelles are investigated by wind tunnel tests. The wind force coefficients of the ellipsoidal nacelles for the wind turbine design and the peak pressure coefficients for the nacelle cover design are proposed based on the experimental data. The wind force coefficients are expressed as functions of yaw angles. The proposed formulas are compared with Eurocode, Germanischer Lloyd and ASCE7-16. It is found that the mean wind force coefficients for the wind turbine nacelles are slightly underestimated in Eurocode. The equivalent maximum and minimum mean pressure coefficients are proposed for use in Design Load Case 6.1 and Design Load Case 6.2 of IEC 61400-1. The peak pressure coefficients are derived using a quasi-steady theory. The proposed equivalent maximum and minimum mean pressure coefficients are much larger than those specified in Germanischer Lloyd.

Comparison of Wind Tunnel Airfoil Performance Data With Wind Turbine Blade Data

1992 ◽  
Vol 114 (2) ◽  
pp. 119-124 ◽  
Author(s):  
C. P. Butterfield ◽  
George Scott ◽  
Walt Musial
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Peak Power ◽  
Unsteady Aerodynamics ◽  
Leading Edge ◽  
Operating Conditions ◽  
Performance Data ◽  
Horizontal Axis Wind Turbine ◽  
Force Coefficients ◽  
Basic Fluid

Horizontal axis wind turbine (HAWT) performance is usually predicted by using wind tunnel airfoil performance data in a blade element momentum theory analysis. This analysis assumes that the rotating blade airfoils will perform as they do in the wind tunnel. However, when stall-regulated HAWT performance is measured in full-scale operation, it is common to find that peak power levels are significantly greater than those predicted. Pitch-controlled rotors experience predictable peak power levels because they do not rely on stall to regulate peak power. This has led to empirical corrections to the stall predictions. Viterna and Corrigan (1981) proposed the most popular version of this correction. But very little insight has been gained into the basic cause of this discrepancy. The National Renewable Energy Laboratory (NREL), funded by the DOE, has conducted the first phase of an experiment which is focused on understanding the basic fluid mechanics of HAWT aerodynamics. Results to date have shown that unsteady aerodynamics exist during all operating conditions and dynamic stall can exist for high yaw angle operation. Stall hysteresis occurs for even small yaw angles and delayed stall is a very persistent reality in all operating conditions. Delayed stall is indicated by a leading edge suction peak which remains attached through angles of attack (AOA) up to 30 degrees. Wind tunnel results show this peak separating from the leading edge at 18 deg AOA. The effect of this anomaly is to raise normal force coefficients and tangent force coefficients for high AOA. Increased tangent forces will directly affect HAWT performance in high wind speed operation. This report describes pressure distribution data resulting from both wind tunnel and HAWT tests. A method of bins is used to average the HAWT data which is compared to the wind tunnel data. The analysis technique and the test set-up for each test are described.

Development and Validation of a CFD Technique for the Aerodynamic Analysis of HAWT

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
S. Gómez-Iradi ◽  
R. Steijl ◽  
G. N. Barakos
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Wind Tunnel Test ◽  
Unsteady Aerodynamics ◽  
Tunnel Wall ◽  
Local Flow ◽  
Flow Angle ◽  
Thrust And Torque

This paper demonstrates the potential of a compressible Navier–Stokes CFD method for the analysis of horizontal axis wind turbines. The method was first validated against experimental data of the NREL/NASA-Ames Phase VI (Hand, et al., 2001, “Unsteady Aerodynamics Experiment Phase, VI: Wind Tunnel Test Configurations and Available Data Campaigns,” NREL, Technical Report No. TP-500-29955) wind-tunnel campaign at 7 m/s, 10 m/s, and 20 m/s freestreams for a nonyawed isolated rotor. Comparisons are shown for the surface pressure distributions at several stations along the blades as well as for the integrated thrust and torque values. In addition, a comparison between measurements and CFD results is shown for the local flow angle at several stations ahead of the wind turbine blades. For attached and moderately stalled flow conditions the thrust and torque predictions are fair, though improvements in the stalled flow regime are necessary to avoid overprediction of torque. Subsequently, the wind-tunnel wall effects on the blade aerodynamics, as well as the blade/tower interaction, were investigated. The selected case corresponded to 7 m/s up-wind wind turbine at 0 deg of yaw angle and a rotational speed of 72 rpm. The obtained results suggest that the present method can cope well with the flows encountered around wind turbines providing useful results for their aerodynamic performance and revealing flow details near and off the blades and tower.

scholarly journals Wind Turbine Wake Modeling in Accelerating Wind Field: A Preliminary Study on a Two-Dimensional Hill

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 153 ◽  
Author(s):  
Omar M. A. M. Ibrahim ◽  
Shigeo Yoshida ◽  
Masahiro Hamasaki ◽  
Ao Takada
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Field ◽  
Complex Terrain ◽  
Wind Farm ◽  
Wind Tunnel Test ◽  
Two Dimensional ◽  
Preliminary Study ◽  
Wake Model

Complex terrain can influence wind turbine wakes and wind speed profiles in a wind farm. Consequently, predicting the performance of wind turbines and energy production over complex terrain is more difficult than it is over flat terrain. In this preliminary study, an engineering wake model, that considers acceleration on a two-dimensional hill, was developed based on the momentum theory. The model consists of the wake width and wake wind speed. The equation to calculate the rotor thrust, which is calculated by the wake wind speed profiles, was also formulated. Then, a wind-tunnel test was performed in simple flow conditions in order to investigate wake development over a two-dimensional hill. After this the wake model was compared with the wind-tunnel test, and the results obtained by using the new wake model were close to the wind-tunnel test results. Using the new wake model, it was possible to estimate the wake shrinkage in an accelerating two-dimensional wind field.

Design Load Case Analysis and Comparison for a 5MW Offwhore Wind Turbine Using FAST, GH Bladed and CFD Method

2015 ◽  
Vol 18 (2) ◽  
pp. 14-21
Author(s):  
Ki-Ha Kim ◽  
Dong-Hyun Kim ◽  
Young-Seob Kwak ◽  
Su-Hyun Kim
Keyword(s):  
Wind Turbine ◽  
Case Analysis ◽  
Load Case ◽  
Design Load ◽  
Cfd Method

WIND TUNNEL TEST FOR CALCULATING WIND FORCES ON SCAFFOLDS WITH BASEBOARD HEIGHT AS A PARAMETER

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Hiroki Takahashi ◽  
Katsutoshi Ohdo ◽  
Seiji Takanashi
Keyword(s):  
Wind Tunnel ◽  
Construction Industry ◽  
Wind Tunnel Test ◽  
Industrial Safety ◽  
Design Codes ◽  
Health Law ◽  
Wind Force ◽  
Force Coefficient ◽  
Safety And Health ◽  
Current Design

The Japanese Industrial Safety and Health Law was revised in March 2009 to introduce new measures concerning accidental falls in the construction industry. This revision mandates the use of guard rails, handrails, and other scaffold components. The wind load criteria and structural specifications of scaffolds are regulated by current design codes. Nevertheless, these provisions do not necessarily comply with the newly incorporated legal requirements because they apply to old-style scaffolds. This study examined the wind force on scaffolds by wind tunnel test, with baseboard height used as a parameter. The wind force coefficient of one story of scaffolds was calculated. Wind force coefficient increased as baseboard height increased. The wind force on the scaffolds equipped with baseboards is 9.2 times that on the scaffolds without baseboards. The baseboard must be greater than or equal to 15 cm to satisfy regulation requirements. The wind force coefficient of scaffolds with a 15 cm baseboard is 1.5 times that of the scaffolds without a baseboard. In scaffold design, baseboard height should be considered to guarantee a suitable wind force coefficient.

E215 Blades vibration characteristics analysis of a teetered-rotor wind turbine by wind tunnel test

2015 ◽  
Vol 2015.20 (0) ◽  
pp. 323-326
Author(s):  
Shuji SUZUKI ◽  
Shigemitsu AOKI ◽  
Kenichi SAKURAI ◽  
Tetsuya KOGAKI ◽  
Chuichi ARAKAWA ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Tunnel Test ◽  
Vibration Characteristics ◽  
Characteristics Analysis

Design of a Wind Tunnel Test Section for Single Airfoil Configuration With Real-Time Lift Force Control

2017 ◽  
Author(s):  
Aline Aguiar da Franca ◽  
Dirk Abel
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Real Time ◽  
Force Control ◽  
Test Section ◽  
Lift Force ◽  
Angle Of Attack ◽  
Wind Tunnel Test ◽  
Wiener Model ◽  
Dynamic Matrix

This article presents a concept of test section for a closed-return wind tunnel, where the lift force of an airfoil, which depends on the angle of attack, is controlled in real-time. This airfoil is used to represent a wind turbine blade. The lift force of the blades is what produces the rotor torque of the wind turbine. This torque determines the amount of energy that will be captured by the wind turbine. The linear dynamics of the motor used to change the angle of attack and the static non-linearity of the airfoil are modeled as a Wiener model. The Quadratic Dynamic Matrix Controller based on Wiener model with linearizing pre-compensation is implemented to keep the lift force constant, which is desirable to avoid mechanical loads for wind turbine applications.

Wind Pressure Coefficients Determination for Pre-Homogenization Storage in Cement Mill

2011 ◽  
Vol 94-96 ◽  
pp. 1026-1030
Author(s):  
Yue Ming Luo ◽  
Yue Yin ◽  
Xi Liang Liu
Keyword(s):  
Wind Tunnel ◽  
Spherical Shell ◽  
Rapid Development ◽  
Wind Tunnel Test ◽  
Wind Pressure ◽  
Wind Engineering ◽  
Pressure Coefficients ◽  
Continuous Innovation ◽  
Structural Style ◽  
Wind Pressures

Due to the increasing of wind disaster, structural wind engineering arouses more and more attention recently, with rapid development on spatial structure and continuous innovation of structural style. The main purpose of structural wind engineering is to calculate the wind pressure coefficients of structure. In this paper, the numerical wind tunnel method (NWTM), based on the Computational Fluid Dynamics (CFD), is applied to study wind load. The wind pressure coefficients of reticulated spherical shell with the 4.6m high wall were first determined, using the NWTM. The results are then compared with the wind tunnel test (WTT) and good agreement is found. The feasibility and reliability of NWTM were then verified. As the second example, NWTM is carried out to predict wind-induced pressure on reticulated spherical shell without wall. Further the distribution behavior of wind pressures on this kind of structures is discussed which could provide professionals the reference for the design of structure.

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