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Wind Energy Proceedings of the Euromech Colloquium

:	Joachim Peinke, Peter Schaumann, Stephan Barth
:	Joachim Peinke, Peter Schaumann, Stephan Barth
:	Wind Energy Proceedings of the Euromech Colloquium
:	Springer-Verlag
:	9783540338666
:	1
:	CHF 190.00
:

:	Wärme-, Energie- und Kraftwerktechnik
:	English

:	340
:	Wasserzeichen/DRM
:	PC/MAC/eReader/Tablet
:	PDF

This book is comprised of the proceedings of the Euromech Colloquium 464b 'Wind Energy'. It comprises reports on basic research, as well as research related to the practical exploitation and application of wind energy. The book describes the atmospheric turbulent wind condition on different time scales, and the interaction of wind turbines with both wind and water flows. These influence the design, operation and maintenance of offshore wind turbines.

1 Offshore Wind Power Meteorology (p. 1-2)

Bernhard Lange

Summary. Wind farms built at offshore locations are likely to become an important part of the electricity supply of the future. For an efficient development of this energy source, in depth knowledge about the wind conditions at such locations is therefore crucial. Offshore wind power meteorology aims to provide this knowledge. This paper describes its scope and argues why it is needed for the efficient development of offshore wind power.

1.1 Introduction

Wind power utilization for electricity production has a huge resource and has proven itself to be capable of producing a substantial share of the electricity consumption. It is growing rapidly and can be expected to contribute substantially to our energy need in the future (GWEC, 2005). The ‘fuel’ of this electricity production is the wind. The wind is, on the other hand, also the most important constraint for turbine design, as it creates the loads the turbines have to withstand.

Therefore, accurate knowledge about the wind is needed for planning, design and operation of wind turbines. Some tasks where speci.c meteorological knowledge is essential are wind turbine design, resource assessment, wind power forecasting, etc. Wind power meteorology has therefore established itself as an important topic in applied meteorology (Petersen et al., 1998). For wind power utilization on land, substantial knowledge and experience has been gained in the last decades, based on the detailed meteorological and climatological knowledge available. Offshore, the meteorological knowledge is less developed since there has been little need to know the wind at heights of wind turbines over coastal waters and any measurements at offshore locations are di.cult and extremely expensive.

The aim of this paper is to describe the scope of offshore wind power meteorology and to argue why this topic should be given more attention both from the meteorological point of view and from the wind power application point of view. The paper is structured in three main sections: First some particular problems of offshore measurements are discussed in Sect. 1.2. This is followed by a section giving examples for meteorological effects specific for offshore conditions. Their importance for wind power application is shown in Sect. 1.4, followed by the conclusion.

1.2 Offshore Wind Measurements

In recent years, measurements with the aim to determine the wind conditions for offshore wind power utilization have been erected at a number of locations (Barthelmie et al., 2004). Offshore wind measurements are a challenging task, not only since an offshore foundation and support structure for the mast are needed, but also because of the challenges to provide an autonomous power supply and data transfer, the difficulties of maintenance and repair in an offshore environment, etc. These difficulties lead to high costs of offshore measurements and often lower data availability compared to locations on land. Additionally, the flow distortion of the self supporting mast usually requires a correction of the measured wind speeds for wind profile measurements (Lange, 2004).

Two measurements, from which results are shown in this paper, are the Rødsand field measurement in the Danish Balitc Sea and the FINO 1 measurement in the German Bight.

	Preface	5
	Contents	7
	List of Contributors	21
	1 Offshore Wind Power Meteorology	32
	1.1 Introduction	32
	1.2 Offshore Wind Measurements	33
	1.3 Offshore Meteorology	33
	1.4 Application to Wind Power Utilization	35
	1.5 Conclusion	36
	References	36
	2 Wave Loads on Wind-Power Plants in Deep and Shallow Water	38
	2.1 A Concept of Wave Design in Shallow Areas	38
	2.2 Deep-Water Wave Data	39
	2.3 Wave Transmission into a Shallow Area Using a Phase- Averaging Model	39
	2.4 Wave Kinematics	41
	2.5 Example of Wave Loads	41
	2.6 Wave Transmission into a Shallow Area Using Boussinesq Models	43
	2.7 Conclusions	43
	2.8 Acknowledgements	43
	References	44
	3 Time Domain Comparison of Simulated and Measured Wind Turbine Loads Using Constrained Wind Fields	45
	3.1 Introduction	45
	3.2 Constrained Stochastic Simulation of Wind Fields	45
	3.3 Stochastic Wind Fields which Encompass Measured Wind Speed Series	46
	3.4 Load Calculations Based on Normal and Constrained Wind Field Simulations	48
	3.5 Comparison between Measured Loads and Calculated Ones Based on Constrained Wind Fields	49
	3.6 Conclusion	50
	References	50
	4 Mean Wind and Turbulence in the Atmospheric Boundary Layer Above the Surface Layer	51
	4.1 Atmospheric Boundary Layers at Larger Heights	51
	4.2 Data from Høvsøre Test Site	52
	4.3 Discussion	54
	References	55
	5 Wind Speed Pro.les above the North Sea	56
	5.1 Theory of Inertially Coupled Wind Profiles (ICWP)	56
	5.2 Comparison to Observations at Horns Rev and FINO1	58
	References	60
	6 Fundamental Aspects of Fluid Flow over Complex Terrain for Wind Energy Applications	61
	6.1 Introduction	61
	6.2 Experimental Setup	62
	6.3 Results	63
	6.4 Conclusions	66
	References	66
	7 Models for Computer Simulation of Wind Flow over Sparsely Forested Regions	67
	7.1 Introduction	67
	7.2 Mathematical Models	67
	7.3 Results	68
	7.4 Conclusions	70
	References	70
	8 Power Performance via Nacelle Anemometry on Complex Terrain	71
	8.1 Introduction and Objectives	71
	8.2 Experimental Installations	71
	8.3 Experimental Analysis	71
	8.4 Numerical Analysis	72
	8.5 Results and Analysis	72
	8.6 Conclusion	74
	References	75
	9 Pollutant Dispersion in Flow Around Bluff - Bodies Arrangement	76
	9.1 Introduction	76
	9.2 Results of Measurements	77
	9.3 Conclusions	79
	References	79
	10 On the Atmospheric Flow Modelling over Complex Relief	81
	10.1 Mathematical Model	81
	10.2 Definition of the Computational Case	83
	10.3 Conclusion	85
	References	85
	11 Comparison of Logarithmic Wind Pro.les and Power Law Wind Profiles and their Applicability for Offshore Wind Profiles	86
	11.1 Wind Profile Laws	86
	11.2 Comparison of Profile Laws	86
	11.3 Application to Offshore Wind Profiles	87
	11.4 Conclusions	89
	References	89
	12 Turbulence Modelling and Numerical Flow Simulation of Turbulent Flows	90
	12.1 Summary	90
	12.2 Introduction	90
	12.3 Governing Equations	91
	12.4 Direct Numerical Simulation	92
	12.5 Statistical Turbulence Modelling	92
	12.6 Subgrid Scale Turbulence Modelling	93
	12.7 Conclusion	95
	References	95
	13 Gusts in Intermittent Wind Turbulence and the Dynamics of their Recurrent Times	97
	13.1 Introduction	97
	13.2 Scaling and Intermittency of Velocity Fluctuations	98
	13.3 Gusts for Fixed Time Increments and Their Recurrent Times	98
	13.4 The Dynamics of Inverse Times: Times Needed for Fluctuations Larger than a Fixed Velocity Thr