-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Experimental Investigation of Wind Turbine/FarmWakes 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

-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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 3/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 4/53

-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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Methodology

Scaled (≈1:600),controllable wind turbine

models with speci�cally

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

-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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Pause & Recap

We are through;

Why is this topic important? XWhat am I seeking? XHow am I seeking? X

Next: What I found out;"Experimental Results"

Single Wind Turbine Wake - Brief PhysicsAtmospheric E�ects on Single Wind Turbine Wake

1 Wake Dynamics2 Spectral Content3 Meandering

Two turbines in tandem arrangement1 E�ect of Yaw on the Flow and Power Output

Wind Farm Studies1 Flow within a wind farm2 Power output and Meandering within a wind farm

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 12/53

-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

-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

-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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Wind Tunnel Setup

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 16/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Wake Dynamics

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 17/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Wake Dynamics: Turbulence Charact.

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 18/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Wake Dynamics: Reynolds Stresses

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 19/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Spectral Content for Single Turbine

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 20/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Spectral Content for Single Turbine

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 21/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Spectral Content for Single Turbine

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 22/53

A.B.L. E�ects - Spectral Content for Single Turbine

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Spectral Content for Single Turbine

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 24/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

A.B.L. E�ects - Spectral Content for Single Turbine

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 25/53

-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

-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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Pause & Recap

We are through;

Single Wind Turbine

Wake - Physics XAtmospheric E�ects onSingle Wind TurbineWake X

1 Wake Dynamics2 Spectral Content3 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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Pause & Recap

We are through;

Single Wind Turbine

Wake - Physics XAtmospheric E�ects onSingle Wind TurbineWake X

1 Wake Dynamics2 Spectral Content3 Meandering

Next:

Two turbines in tandemarrangement

1 E�ect of Yaw on the Flow

and Power Output

Wind Farm Studies1 Flow within a wind farm2 Power output and

Meandering within a wind

farm

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 29/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Active Wake Control: E�ect of Yawing

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 30/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Active Wake Control: E�ect of Yawing on Flow

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 31/53

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Active Wake Control: E�ect of Yawing on Power Output

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 32/53

-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

-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

-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

-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

-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

-Introduction -Objective & Methodology -Experimental Results -Analytical Models & CFD -Conlusion

Pause & Recap

We are through;

Why is this topic important? X

What am I seeking? X

How am I seeking? X

What did I �nd out: Experimental Results X

Next: Comparative Studies with Analytical models and simple CFD

Approach

Emre Barlas, EA Exp. Study of WT Wakes, Public Pres. June 38/53

Why Analytical Models

-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

-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

-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

-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

Single Turbine Comparison: Analytical Models & CFD

-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

-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

-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

-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

-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 in�ow

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.

E�ect 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

-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

-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 in�ow

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