[Experimental Investigation of Wind Turbine/Farm Wakes in a Boundary Layer Wind Tunnel] -Research M.Sc. Thesis, VKI,2014 June - Public Presentation E.B. http://www.emrebarlas.com/

1. -Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion
Experimental Investigation of Wind Turbine/Farm
Wakes in a Boundary Layer Wind Tunnel
Emre Barlas
EA Department
Supervisor: Jeroen v. Beeck
Advisor: Sophia Buckingham
June 25, 2014
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 1/53

2. -Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion
Table of contents
1 Introduction
2 Objective & Methodology
3 Experimental Results
4 Analytical Models & Simple CFD Approach
5 Conclusion & Future Work
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 2/53

3. -Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 3/53

4. -Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 4/53

9. -Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion
Aim of the project
Contribute to the understanding of
Interaction between ABL-Wind farm wakes
Meandering phenomenon,crucial
for loading on wind turbines and
lifetime
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 9/53

10. -Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion
Methodology
Scaled (≈1:600),
controllable wind turbine
models with specically
designed blades
Tests are carried out in a
boundary layer wind
tunnel, where the turbine
models are fully
immersed in the 'A.B.L.'
(VKI - L1B)
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 10/53

11. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Experimental Techniques
2D-2C PIV
Spatially Resolved
3C-HWA
Time Resolved
2D-3C PIV
Spatially Resolved
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 11/53

12. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Pause Recap
We are through;
Why is this topic important?
What am I seeking?
How am I seeking?
Next: What I found out;Experimental Results
Single Wind Turbine Wake - Brief Physics
Atmospheric Eects on Single Wind Turbine Wake
1 Wake Dynamics
2 Spectral Content
3 Meandering
Two turbines in tandem arrangement
1 Eect of Yaw on the Flow and Power Output
Wind Farm Studies
1 Flow within a wind farm
2 Power output and Meandering within a wind farm
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 12/53

13. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Single Wind Turbine Wake - Brief Physics
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 13/53

14. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Single Wind Turbine Wake - Brief Physics
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 14/53

15. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Single Wind Turbine Wake - Brief Physics
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 15/53

16. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Wind Tunnel Setup
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 16/53

17. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Wake Dynamics
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 17/53

18. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Wake Dynamics: Turbulence Charact.
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 18/53

19. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Wake Dynamics: Reynolds Stresses
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 19/53

20. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Spectral Content for Single Turbine
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 20/53

21. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Spectral Content for Single Turbine
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 21/53

22. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Spectral Content for Single Turbine
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 22/53

23. A.B.L. Eects - Spectral Content for Single Turbine

24. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Spectral Content for Single Turbine
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 24/53

25. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
A.B.L. Eects - Spectral Content for Single Turbine
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 25/53

26. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Single Turbine Wake Meandering
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 26/53

27. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Single Turbine Wake Meandering
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 27/53

28. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Pause Recap
We are through;
Single Wind Turbine
Wake - Physics
Atmospheric Eects on
Single Wind Turbine
Wake
1 Wake Dynamics
2 Spectral Content
3 Meandering
Conclusions:
Higher Turbulence → Earlier
Wake Recovery BUT Higher
Fatigue.
Spectral Content → Turbine as
'Active Filter'.
Meandering → periodic
behaviour → for Single Turbine
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 28/53

29. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Pause Recap
We are through;
Single Wind Turbine
Wake - Physics
Atmospheric Eects on
Single Wind Turbine
Wake
1 Wake Dynamics
2 Spectral Content
3 Meandering
Next:
Two turbines in tandem
arrangement
1 Eect of Yaw on the Flow
and Power Output
Wind Farm Studies
1 Flow within a wind farm
2 Power output and
Meandering within a wind
farm
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 29/53

30. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Active Wake Control: Eect of Yawing
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 30/53

31. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Active Wake Control: Eect of Yawing on Flow
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 31/53

32. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Active Wake Control: Eect of Yawing on Power Output
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 32/53

33. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Studies - Setup
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 33/53

34. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Studies - Flow within a Wind Farm
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 34/53

35. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Studies - Power within a Wind Farm
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 35/53

36. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Studies - Meandering within a Wind Farm
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 36/53

37. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Studies - Meandering within a Wind Farm
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 37/53

38. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Pause Recap
We are through;
Why is this topic important?
What am I seeking?
How am I seeking?
What did I nd out: Experimental Results
Next: Comparative Studies with Analytical models and simple CFD
Approach
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 38/53

39. Why Analytical Models

40. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Simple CFD Approach
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 40/53

41. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Simple CFD Approach
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 41/53

42. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
CFD output for single turbine (NEXT SLIDE)
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 42/53

43. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Single Turbine Comparison: CFD
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 43/53

44. Single Turbine Comparison: Analytical Models CFD

45. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
CFD output Wind Farm (NEXT SLIDE)
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 45/53

46. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm CFD Output
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 46/53

47. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Comparison: CFD
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 47/53

48. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Wind Farm Comparison: CFD
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 48/53

49. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Conclusions
Single,double turbine and wind farm investigations were carried
out with scaled experimental models under various inow
conditions
The atmospheric turbulence is an important factor on the
wake recovery. BUT it is not always advantageous
Spectral content could be a way to parametrize the wake
dynamics.
Eect of yawing the upstream turbine steers the wake, BUT in
this study it did not yield power output increase of the array.
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 49/53

50. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Conclusions
The very basic analytical models perform still poorly, but with
the increasing knowledge the newer versions are much more
accurate.
CFD is still a way to go, however if it is aimed to understand
the physics of the ow, it is important to use eddy resolving
turbulence models. (the structures in the atmosphere are
important for loading on wind turbines)
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 50/53

51. -Introduction -Objective Methodology -Experimental Results -Analytical Models CFD -Conlusion
Future Work
The wake is fully dependent on the Thrust, so strain gauge
measurements are required at various TSR
Studies on ow within the wind farms under various inow
conditions
Introducing another boundary layer with intermediate cups
Power output studies by varying wind Farm topology and wind
direction
Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 51/53