Wind Energy - Proceedings of the Euromech Colloquium

Preface

Contents

List of Contributors

1 Offshore Wind Power Meteorology

1.1 Introduction

1.2 Offshore Wind Measurements

1.3 Offshore Meteorology

1.4 Application to Wind Power Utilization

1.5 Conclusion

References

2 Wave Loads on Wind-Power Plants in Deep and Shallow Water

2.1 A Concept of Wave Design in Shallow Areas

2.2 Deep-Water Wave Data

2.3 Wave Transmission into a Shallow Area Using a Phase- Averaging Model

2.4 Wave Kinematics

2.5 Example of Wave Loads

2.6 Wave Transmission into a Shallow Area Using Boussinesq Models

2.7 Conclusions

2.8 Acknowledgements

References

3 Time Domain Comparison of Simulated and Measured Wind Turbine Loads Using Constrained Wind Fields

3.1 Introduction

3.2 Constrained Stochastic Simulation of Wind Fields

3.3 Stochastic Wind Fields which Encompass Measured Wind Speed Series

3.4 Load Calculations Based on Normal and Constrained Wind Field Simulations

3.5 Comparison between Measured Loads and Calculated Ones Based on Constrained Wind Fields

3.6 Conclusion

References

4 Mean Wind and Turbulence in the Atmospheric Boundary Layer Above the Surface Layer

4.1 Atmospheric Boundary Layers at Larger Heights

4.2 Data from Høvsøre Test Site

4.3 Discussion

References

5 Wind Speed Pro.les above the North Sea

5.1 Theory of Inertially Coupled Wind Profiles (ICWP)

5.2 Comparison to Observations at Horns Rev and FINO1

References

6 Fundamental Aspects of Fluid Flow over Complex Terrain for Wind Energy Applications

6.1 Introduction

6.2 Experimental Setup

6.3 Results

6.4 Conclusions

References

7 Models for Computer Simulation of Wind Flow over Sparsely Forested Regions

7.1 Introduction

7.2 Mathematical Models

7.3 Results

7.4 Conclusions

References

8 Power Performance via Nacelle Anemometry on Complex Terrain

8.1 Introduction and Objectives

8.2 Experimental Installations

8.3 Experimental Analysis

8.4 Numerical Analysis

8.5 Results and Analysis

8.6 Conclusion

References

9 Pollutant Dispersion in Flow Around Bluff - Bodies Arrangement

9.1 Introduction

9.2 Results of Measurements

9.3 Conclusions

References

10 On the Atmospheric Flow Modelling over Complex Relief

10.1 Mathematical Model

10.2 Definition of the Computational Case

10.3 Conclusion

References

11 Comparison of Logarithmic Wind Pro.les and Power Law Wind Profiles and their Applicability for Offshore Wind Profiles

11.1 Wind Profile Laws

11.2 Comparison of Profile Laws

11.3 Application to Offshore Wind Profiles

11.4 Conclusions

References

12 Turbulence Modelling and Numerical Flow Simulation of Turbulent Flows

12.1 Summary

12.2 Introduction

12.3 Governing Equations

12.4 Direct Numerical Simulation

12.5 Statistical Turbulence Modelling

12.6 Subgrid Scale Turbulence Modelling

12.7 Conclusion

References

13 Gusts in Intermittent Wind Turbulence and the Dynamics of their Recurrent Times

13.1 Introduction

13.2 Scaling and Intermittency of Velocity Fluctuations

13.3 Gusts for Fixed Time Increments and Their Recurrent Times

13.4 The Dynamics of Inverse Times: Times Needed for Fluctuations Larger than a Fixed Velocity Threshold

References

14 Report on the Research Project OWID – Offshore Wind Design Parameter

14.1 Summary

14.2 Relevant Standards and Guidelines

14.3 Normal Wind Pro.le

14.4 Normal Turbulence Model

14.5 Extreme Wind Conditions

14.6 Outlook

14.7 Acknowledgement

References

15 Simulation of Turbulence, Gusts and Wakes for Load Calculations

15.1 Introduction

15.2 Simulation over Flat Terrain

15.3 Constrained Gaussian Simulation

15.4 Wakes

References

16 Short Time Prediction of Wind Speeds from Local Measurements

16.1 Wind Speed Predictions

16.2 Prediction of Wind Gusts

References

17 Wind Extremes and Scales: Multifractal Insights and Empirical Evidence

17.1 Atmospheric Dynamics, Cascades and Statistics

17.2 Extremes

17.3 Discussion and Conclusion

References

18 Boundary-Layer In.uence on Extreme Events in Stratified Flows over Orography

18.1 Introduction

18.2 Experimental Procedure

18.3 Basic Flow Pattern

18.4 Downstream Slip Condition

18.5 Boundary Layer and Wave Field Interaction

18.6 Concluding Remarks

References

19 The Statistical Distribution of Turbulence Driven Velocity Extremes in the Atmospheric Boundary Layer – Cartwright/ Longuet-Higgins Revised

19.1 Introduction

19.2 Model

References

20 Superposition Model for Atmospheric Turbulence

20.1 Introduction

20.2 Superposition Model

20.3 Conclusions and Outlook

References

21 Extreme Events Under Low-Frequency Wind Speed Variability and Wind Energy Generation

21.1 Introduction

21.2 Mathematical Background

21.3 Results and Conclusions

21.4 Acknowledgments

References

22 Stochastic Small-Scale Modelling of Turbulent Wind Time Series

22.1 Introduction

22.2 Consistent Modelling of Velocity and Dissipation

22.3 Re.ned Modelling: Stationarity and Skewness

22.4 Statistics of the Arti.cial Velocity Signal

References

23 Quantitative Estimation of Drift and Diffusion Functions from Time Series Data

23.1 Introduction

23.2 Direct Estimation of Drift and Diffusion

23.3 Stability of the Limiting Procedure

23.4 Finite Length of Time Series

23.5 Conclusion

References

24 Scaling Turbulent Atmospheric Stratification: A Turbulence/ Wave Wind Model

24.1 Introduction

24.2 An Extreme Unlocalized (Wave) Extension

References

25 Wind Farm Power Fluctuations

25.1 Introduction

25.2 Test Site

25.3 PSDs

25.4 Coherence

25.5 Conclusion

References

26 Network Perspective of Wind-Power Production

26.1 Introduction

26.2 Robustness in a Critical-Infrastructure Network Model

26.3 Two Wind-Power Related Model Extensions

26.4 Outlook

References

27 Phenomenological Response Theory to Predict Power Output

27.1 Introduction

27.2 Power Curve from Measurement Data

27.3 Relaxation Model

27.4 Discussion and Conclusion

References

28 Turbulence Correction for Power Curves

28.1 Introduction

28.2 Turbulence and Its Impact on Power Curves

28.3 Results

28.4 Conclusion

References

29 Online Modeling of Wind Farm Power for Performance Surveillance and Optimization

29.1 Wind Turbine Power Modeling Approach

29.2 Measurements and Simulation

29.3 Results

References

30 Uncertainty of Wind Energy Estimation

30.1 Introduction

30.2 Wind Climate of Hungary

30.3 The Uncertainty of the Power Law Wind Pro.le Estimation

30.4 Inter-Annual Variability of Wind Energy

30.5 Conclusion

References

31 Characterisation of the Power Curve for Wind Turbines by Stochastic Modelling

31.1 Introduction

31.2 Simple Relaxation Model

31.3 Langevin Method

31.4 Data Analysis

31.5 Conclusion and Outlook

References

32 Handling Systems Driven by Di.erent Noise Sources: Implications for Power Curve Estimations

32.1 Power Curve Estimation in a Turbulent Environment

32.2 Conclusions and Outlook

References

33 Experimental Researches of Characteristics of Windrotor Models with Vertical Axis of Rotation

33.1 Introduction

33.2 Experimental Installation and Models

33.3 Performance Characteristics of Windrotor Models

33.4 Results

34 Methodical Failure Detection in Grid Connected Wind Parks

34.1 Problem Description

34.2 Doubly-fed Induction Generators

34.3 Measurements

34.4 Conclusions

References

35 Modelling of the Transition Locations on a 30% thick Airfoil with Surface Roughness

35.1 Introduction

35.2 Measurements

35.3 Modelling

35.4 Results and Discussion

35.5 Conclusions

References

36 Helicopter Aerodynamics with Emphasis Placed on Dynamic Stall

36.1 Introduction

36.2 The Phenomenon Dynamic Stall

36.3 Numerical and Experimental Results for the Typical Helicopter Airfoil OA209

36.4 Conclusions

References

37 Determination of Angle of Attack (AOA) for Rotating Blades

37.1 Introduction

37.2 Determination of Angle of Attack

37.3 Numerical Results and Comparisons

37.4 Conclusion

References

38 Unsteady Characteristics of Flow Around an Airfoil at High Angles of Attack and Low Reynolds Numbers

38.1 Introduction

38.2 Test Facility and Setup

38.3 Experimental Results and Discussions

38.4 Conclusions

References

39 Aerodynamic Multi-Criteria Shape Optimization of VAWT Blade Profile by Viscous Approach

39.1 Introduction

39.2 Physical Model

39.3 Blade Profile Optimization

39.4 Numerical Results

39.5 Conclusion and Prospects

References

40 Rotation and Turbulence Effects on a HAWT Blade Airfoil Aerodynamics

40.1 Introduction

40.2 Experiment

40.3 Results and Discussion

40.4 Conclusion

References

41 3D Numerical Simulation and Evaluation of the Air Flow Through Wind Turbine Rotors with Focus on the Hub Area

41.1 Introduction

41.2 Method

41.3 Results

41.4 Perspective

References

42 Performance of the Risø-B1 Airfoil Family for Wind Turbines

42.1 Introduction

42.2 The Wind Tunnel

42.3 Results

42.4 Conclusions

42.5 Acknowledgements

References

43 Aerodynamic Behaviour of a New Type of Slow-Running VAWT

43.1 Introduction

43.2 Description of the Savonius Rotors

43.3 Description of the Numerical Model

43.4 Results

43.5 Conclusion

References

44 Numerical Simulation of Dynamic Stall using Spectral/ hp Method

44.1 Introduction

44.2 The Spectral/hp Method

44.3 The NekTar Code

44.4 First Results

44.5 Outlook

References

45 Modeling of the Far Wake behind a Wind Turbine

45.1 Extended Joukowski Model

45.2 Unsteady Behavior

45.3 Conclusions

References

46 Stability of the Tip Vortices in the Far Wake behind a Wind Turbine

46.1 Theory: Analysis of the Stability

46.2 Application of the Analysis

46.3 Conclusions

References

47 Modelling Turbulence Intensities Inside Wind Farms

47.1 Description of the Model

47.2 Comparison of the Model with Wake Measurements

47.3 Conclusion

References

48 Numerical Computations of Wind Turbine Wakes

48.1 Numerical Method

48.2 Simulation

References

49 Modelling Wind Turbine Wakes with a Porosity Concept

49.1 Introduction

49.2 Experimental Set-up

49.3 Results for Homogeneous Freestream Conditions

49.4 Results for Shear Freestream Conditions

49.5 Conclusion

References

50 Prediction of Wind Turbine Noise Generation and Propagation based on an Acoustic Analogy

50.1 Introduction

50.2 Problem De.nition

50.3 Results

References

51 Comparing WAsP and Fluent for Highly Complex Terrain Wind Prediction

51.1 Introduction

51.2 Alaiz Test Site

51.3 Description of the Models

51.4 Results

51.5 Conclusions

References

52 Fatigue Assessment of Truss Joints Based on Local Approaches

52.1 Introduction

52.2 Concepts

52.3 Examples

52.4 Conclusion

References

53 Advances in Offshore Wind Technology

53.1 Introduction

53.2 Wind Turbine Technology

53.3 Substructure Technology

53.4 Installation Methods

References

54 Beneffts of Fatigue Assessment with Local Concepts

54.1 Introduction

54.2 Applied Local Concepts

54.3 Comparison of Fatigue Design for a Tripod

54.4 Conclusion

References

55 Extension of Life Time of Welded Fatigue Loaded Structures

55.1 Introduction

55.2 Background

55.3 Experimental Studies

55.4 Results

55.5 Conclusions

References

56 Damage Detection on Structures of O.shore Wind Turbines using Multiparameter Eigenvalues

56.1 Introduction

56.2 The Multiparameter Eigenvalue Method

56.3 Validation of the Method

56.4 Outlook

References

57 Influence of the Type and Size of Wind Turbines on Anti- Icing Thermal Power Requirements for Blades

57.1 Introduction

57.2 Analysis of the Results

57.3 Anti-Icing Power as a Function of the Machine Size

57.4 Anti-Icing Power as a Function of the Machine Type

57.5 Conclusions

References

58 High-cycle Fatigue of “Ultra-High Performance Concrete” and “Grouted Joints” for O.shore Wind Energy Turbines

58.1 Introduction

58.2 Ultra-High Performance Concrete

58.3 Ultra-High Performance Concrete in Grouted Joints

58.4 Conclusions

References

59 A Modular Concept for Integrated Modeling of O . shore WEC Applied to Wave- Structure Coupling

59.1 Introduction

59.2 Integrated Modeling

59.3 Modeling of Wave Loads on the Support Structure Offshore Wind Energy Turbines

59.4 Future Demands

References

60 Solutions of Details Regarding Fatigue and the Use of High-Strength Steels for Towers of Offshore Wind Energy Converters

60.1 Introduction

60.2 Fatigue Tests

60.3 Finite-Element Analyses

References

61 On the Influence of Low-Level Jets on Energy Production and Loading of Wind Turbines

61.1 Introduction

61.2 Data and Methods

61.3 Results

61.4 Conclusions

References

62 Reliability of Wind Turbines

62.1 Introduction

62.2 Data Basis

62.3 Break Down of Wind Turbines

62.4 Malfunctions of Components

62.5 Conclusion

References