Influence of pitch motion on the wake of floating wind turbine models

Transcription

1 Influence of pitch motion on the wake of floating wind turbine models S. Rockel* 1, J. Peinke 1, R. B. Cal 2 and M. Hölling 1 1 ForWind, Institute of Physics - University of Oldenburg 2 Dept. of Mechanical and Materials Engineering, Portland State University *contact: stanislav.rockel@uni-oldenburg.de

2 Motivation tripods and monopiles feasible in shallow water 2

3 Motivation tripods and monopiles feasible in shallow water floating platforms are a solution for offshore wind energy in deep water [Henderson, 2009] Statoil - Hywind greenunivers.com 2

4 Motivation tripods and monopiles feasible in shallow water floating platforms are a solution for offshore wind energy in deep water [Henderson, 2009] floating platform adds dynamics to system [Jonkman, 2009; Sebastian, 2012] Statoil - Hywind greenunivers.com 2

5 Motivation tripods and monopiles feasible in shallow water floating platforms are a solution for offshore wind energy in deep water [Henderson, 2009] floating platform adds dynamics to system [Jonkman, 2009; Sebastian, 2012] Statoil - Hywind greenunivers.com changed inflow and wake characteristics 2

6 Motivation tripods and monopiles feasible in shallow water floating platforms are a solution for offshore wind energy in deep water [Henderson, 2009] floating platform adds dynamics to system [Jonkman, 2009; Sebastian, 2012] Statoil - Hywind greenunivers.com changed inflow and wake characteristics Experimental investigation of wake development 2

7 Objectives - Approach understand the differences between a fixed turbine and a floating turbine 3

8 Objectives - Approach understand the differences between a fixed turbine and a floating turbine wind tunnel experiments with model wind turbines using stereo particle image velocimetry (SPIV) 3

9 Objectives - Approach understand the differences between a fixed turbine and a floating turbine wind tunnel experiments with model wind turbines using stereo particle image velocimetry (SPIV) simplification of floating turbine: 1D streamwise oscillation (pitch motion) 3

10 Objectives - Approach understand the differences between a fixed turbine and a floating turbine wind tunnel experiments with model wind turbines using stereo particle image velocimetry (SPIV) simplification of floating turbine: 1D streamwise oscillation (pitch motion) comparison of inflow and wake development near wakes of up- and downstream turbines 3

11 Experimental setup wind test section length = 5 m y x tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. 4

12 tunnel height = 0.8 m passive grid Experimental setup wind test section length = 5 m y x distance to turbine = 2 m wind tunnel at Portland State Univ. 4

13 Experimental setup passive grid wind test section length = 5 m y x vertical strakes tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. 4

14 Experimental setup passive grid wind test section length = 5 m y x vertical strakes Ti: 9% tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. 4

15 Experimental setup passive grid wind test section length = 5 m y x vertical strakes Ti: 9% D = 0.2 m tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. 4

16 Experimental setup passive grid SPIV: op)cal flow measurements 2D- 3C planes: center of tower fixed case laser sheets wind test section length = 5 m y x vertical strakes Ti: 9% D = 0.2 m PIV area 0.2 m x 0.2 m tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. planes measured at 0.5D - 7D 4

17 Experimental setup passive grid wind SPIV: op)cal flow measurements 2D- 3C planes: center of tower fixed case test section length = 5 m y x vertical strakes Ti: 9% floa)ng condi)on: 1D streamwise oscilla)on floa)ng case PIV triggered on turbine posi)on 2500 images / plane D = 0.2 m PIV area 0.2 m x 0.2 m laser sheets tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. planes measured at 0.5D - 7D 4

18 Inflow setup vertical strakes passive grid wind test section length = 5 m y x Ti: 9% D = 0.2 m tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. 5

19 Inflow: averaged streamwise component <U/Uhh> free inflow <U/Uhh> X/D 6

20 Inflow: averaged streamwise component <U/Uhh> free inflow <U/Uhh> X/D 6

21 Inflow: averaged streamwise component <U/Uhh> <U/Uhh> 1.0 free inflow <U/Uhh> X/D X/D 6

22 Inflow: averaged streamwise component <U/Uhh> <U/Uhh> 1.0 free inflow <U/Uhh> X/D X/D 6

23 Inflow: averaged streamwise component <U/Uhh> <U/Uhh> 1.0 free inflow <U/Uhh> X/D 0.85 <U/Uhh> X/D X/D 6

24 Inflow: averaged streamwise component <U/Uhh> <U/Uhh> 1.0 free inflow <U/Uhh> X/D 0.85 <U/Uhh> X/D X/D 6

25 Inflow: averaged vertical component <V/Uhh> free inflow <V/Uhh> X/D 7

26 Inflow: averaged vertical component <V/Uhh> <V/Uhh> 0.04 free inflow <V/Uhh> X/D X/D 7

27 Inflow: averaged vertical component <V/Uhh> <V/Uhh> 0.04 free inflow <V/Uhh> X/D <V/Uhh> X/D X/D 7

28 Inflow: averaged turbulence intensity <σu/uhh> free inflow <σu/uhh> X/D 8

29 Inflow: averaged turbulence intensity <σu/uhh> <σu/uhh> 0.11 free inflow <σu/uhh> X/D X/D 8

30 Inflow: averaged turbulence intensity <σu/uhh> <σu/uhh> 0.11 free inflow <σu/uhh> X/D 0.09 <σu/uhh> X/D X/D 8

31 passive grid Wake of turbine 1 laser sheets wind test section length = 5 m y x vertical strakes D = 0.2 m PIV area 0.2 m x 0.2 m tunnel height = 0.8 m distance to turbine = 2 m wind tunnel at Portland State Univ. planes measured at 0.5D - 7D 9

32 Averaged streamwise velocity <U/Uhh> <U/Uhh> [comp. Vermeer, 2003] 10

33 Averaged streamwise velocity <U/Uhh> <U/Uhh> [comp. Vermeer, 2003] <U/Uhh> 0.5 D 7D 10

34 Averaged streamwise velocity <U/Uhh> <U/Uhh> [comp. Vermeer, 2003] -10% <U/Uhh> +5% 0.5 D 7D 10

35 Averaged vertical velocity <V/Uhh> <V/Uhh> 11

36 Averaged vertical velocity <V/Uhh> <V/Uhh> <V/Uhh> 0.5 D 7D 11

37 Averaged vertical velocity <V/Uhh> <V/Uhh> 0 m/s <V/Uhh> 0.25 m/s 0.5 D 7D 11

38 Averaged turbulence intensity <σu/uhh> <σu/uhh> 12

39 Averaged turbulence intensity <σu/uhh> <σu/uhh> <σu/uhh> 0.5 D 7D 12

40 Setup: two turbines vertical strakes y x D = 0.2 m laser sheets tunnel height = 0.8 m passive grid wind test section length = 5 m Ti: 9% distance = 1.5 m = 7.5D wind tunnel at Portland State Univ. 13

41 Setup: two turbines vertical strakes y x D = 0.2 m laser sheets tunnel height = 0.8 m passive grid wind test section length = 5 m Ti: 9% distance = 1.5 m = 7.5D wind tunnel at Portland State Univ. 13

42 Inflow profiles <U/Uhh> at 0.5D upstream <U/Uhh> 14

43 Inflow profiles <U/Uhh> at 0.5D upstream <U/Uhh> <U/Uhh> 14

44 Turbulence intensity profiles <σu/uhh> at 0.5D upstream <σu/uhh> 15

45 Turbulence intensity profiles <σu/uhh> at 0.5D upstream <σu/uhh> <σu/uhh> 15

46 Near wake profiles <U/Uhh> at 1D downstream <U/Uhh> 16

47 Near wake profiles <U/Uhh> at 1D downstream <U/Uhh> <U/Uhh> 16

48 Summary & Conclusions Blockage changes inflow profile Pitch motion has strong impact on wake Vertical trend in all quantities Increased vertical flow Reduced turbulence intensity in far wake Changed inflow profile for downstream turbine has no influence on near wake 17

49 Thank you! Questions? Statoil - Hywind Acknowledgements: Elizabeth Camp German Environmental Foundation greenunivers.com Experimental study on influence of pitch motion on the wake of a floating wind turbine model, Rockel et al., Energies, submitted

50 spanwise velocity <W/Uhh> <W/Uhh> 0.5 D 7D 19

51 Near wake profiles <V/Uhh> at 1D downstream <V/Uhh> <V/Uhh> 20

52 Near wake turbulence intensity <σu/uhh> at 1D downstream <σu/uhh> <σu/uhh> 21

53 Comparison with wake models: fixed shape and magnitude of deficit predicted for X = 3D and 4.5D 22

54 Comparison with wake models: floating vertical displacement NOT captured 23