Cel THE UTILIZATION OF WIND ENERGY ON MANY SIGNIFICANT SCALE REQUIRES LARGE NUMBERS OF WIND TURBINES. STUDIES OF THE INTERACTIONS IN ARRAYS OF WIND TURBINES HAVE THEREFORE FORMED AN IMPORTANT PART OF SEVERAL NATIONAL WIND ENERGY PROGRAMMES. THE INSTALLATION AT NIBE, WITH TWO 40 M DIAMETER WIND TURBINES SITED IN LEVEL TERRAIN, 200 M APART, PROVIDES A EXCELLENT OPPORTUNITY TO STUDY MACHINE INTERACTIONS IN DETAIL. THE AIM OF THE PROJECT IS TO MEASURE THE POWER LOSSES AND INCREASED BLADE LOADS WHEN THE MACHINES INTERACT AND TO DEVELOP PREDICTIVE TECHNIQUES WHICH ARE GENERALLY APPLICABLE, TAKING INTO ACCOUNT THE ROTOR CHARACTERISTICS, THE EFFECT OF TURBULENCE ON WAKE DECAY RATES AND THE EFFECT ON ROTOR PERFORMANCE OF TOTAL OR PARTIAL IMMERSION IN A WAKE. A considerable body of wake and turbine data has been collected from the 2 630 kW Nibe turbines in Denmark, which are separated by 200m (5 rotor diameters). Information has been obtained on: the velocity deficits and turbulence intensities within a wake under a variety of operating conditions at up to 7.5 rotor diameters downstream of a turbine; the velocity deficits and turbulence intensities within a double wake at up to 2.5 rotor diameters behind the second rotor; the spectral characteristics of the turbulence in the wake; the power losses experienced by a rotor when operating in a wake; the dynamic loads imposed on a rotor when operating in a wake region.The fatigue damage rates and external loads which result from operating a turbine in a wake region have also been examined.AN UNDERSTANDING OF THE WAKE STRUCTURE BEHIND WIND-TURBINES IS IMPORTANT FOR THE DESIGN OF TURBINE ARRAYS. MOST INFORMATION ON WAKE DEVELOPMENT AND DECAY HAS BEEN DERIVED FROM SMALL-SCALE WIND TUNNEL TESTS AND IS SUBJECT TO A NUMBER OF UNCERTAINTIES. THIS PROJECT INVOLVES AN EXTENSIVE PROGRAMME OF MEASUREMENTS AROUND THE TWO NIBE WIND-TURBINES AND IS INTENDED TO PROVIDE DATA ON WAKE BEHAVIOUR IN A FULL-SCALE ATMOSPHERIC ENVIRONMENT. THE EXPERIMENTAL AND ANALYTICAL PART OF THE PROJECT ARE NOW ESSENTIALLY COMPLETE AND THE FINAL REPORTS ARE NOW BEING WRITTEN. DETAILED INFORMATION HAS BEEN COLLECTED ON THE VELOCITY DEFICITS AND TURBULENCE INTENSITIES ENCOUNTERED IN A WAKE UNDER A VARIETY OF OPERATING CONDITIONS. IN ADDITION, DATA ON THE POWER LOSSES AND STRUCTURAL LOADS IMPOSED ON A WIND-TURBINE WHEN OPERATING IN A WAKE HAVE BEEN OBTAINED. THE MEASURED WAKE STRUCTURE HAS BEEN COMPARED WITH THE PREDICTIONS OF TWO COMPUTATIONAL MODELS, AN EDDY-VISCOSITY MODEL (NWAKE) AND A SEMI-EMPIRICAL KINEMATIC MODEL (FARMS). THE MODELS YIELD ENCOURAGING RESULTS BUT, IN EACH CASE, IT IS NECESSARY TO ADJUST THE EMPIRICAL PARAMETERS USED IN THE CODE IF GOOD AGREEMENT WITH THE EXPERIMENTAL DATA IS REQUIRED. TURBULENCE INTENSITIES OF TYPICALLY 15 % ARE MEASURED IN THE WAKE AT 4D DOWNSTREAM AND ARE MARKEDLY INCREASED ABOVE THE AMBIENT LEVEL OF 9 %. EXAMINATION OF THE TURBULENCE SPECTRA REVEALS A BROAD BAND STRUCTURE WITH NO NARROW BAND FEATURES AT HARMONICS OF THE BLADE PASSING FREQUENCY. THE CHARACTERISTIC FREQUENCY OF THE TURBULENCE IN THE WAKE IS, HOWEVER, RAISED COMPARED WITH THE FREE STREAM. SIGNIFICANT POWER LOSSES ARE OBSERVED ON THE DOWNSTREAM MACHINE FOR WIND DIRECTIONS WITHIN +/- 20 DEGREES CELSIUS OF THE INTER-MACHINE AXIS. LOSSES OF UP TO 60 % ARE FOUND WHEN A TURBINE IS COMPLETELY IMMERSED IN THE WAKE OF THE UPSTREAM MACHINE. THESE LOSSES ARE IN REASONABLE AGREEMENT WITH THOSE PREDICTED THEORETICALLY. MARKEDLY INCREASED DYNAMIC LOADS ARE EXPERIENCED BY A ROTOR OPERATING IN A WAKE. IT HAS PROVED POSSIBLE TO RELATE THE STOCHASTIC AND DETERMINISTIC CONTRIBUTIONS TO THESE LOADS TO THE MEASURED WAKE STRUCTURE. INFORMATION ON THE CORRESPONDING INCREASE IN THE FATIGUE DAMAGE RATE HAS ALSO BEEN OBTAINED. Dziedzina nauki engineering and technologymechanical engineeringvehicle engineeringaerospace engineeringaircraftengineering and technologyenvironmental engineeringenergy and fuelsrenewable energywind power Program(-y) FP1-ENNONUC 3C - Research and development programme (EEC) in the field of Non-Nuclear Energy, 1985-1988 Temat(-y) Data not available Zaproszenie do składania wniosków Data not available System finansowania CSC - Cost-sharing contracts Koordynator National Power plc Wkład UE Brak danych Adres Kelvin Avenue KT22 7SE Leatherhead Zjednoczone Królestwo Zobacz na mapie Koszt całkowity Brak danych Uczestnicy (5) Sortuj alfabetycznie Sortuj według wkładu UE Rozwiń wszystko Zwiń wszystko DEFU Dania Wkład UE Brak danych Adres Zobacz na mapie Koszt całkowity Brak danych ELECTRICITY SUPPLY BOARD (ESB) Irlandia Wkład UE Brak danych Adres Zobacz na mapie Koszt całkowity Brak danych Garrad Hassan and Partners Ltd Zjednoczone Królestwo Wkład UE Brak danych Adres Zobacz na mapie Koszt całkowity Brak danych RISO Dania Wkład UE Brak danych Adres NATIONAL LABORATORY Zobacz na mapie Koszt całkowity Brak danych TNO Niderlandy Wkład UE Brak danych Adres Zobacz na mapie Koszt całkowity Brak danych
