Wind power in forest - the effects of

clearings

Johanna Matsfelt

Acknowledgements

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OUTLINE

• SOWFA by NREL

• Implementation of the forest

• Validation

• Test cases

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SOWFA by NREL

Figure: Overview SOWFA, source NREL

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Implementation of the forest

Add terms to the transport equations

• MomentumFf ,i = −CDafUui

• Potential temperatureSh = ∂

∂z(Qhexp(−γAc))

Ac =∫h

zaf dz

Model by: Schumann and Shaw, 1992

Johanna Matsfelt 2017-04-04 5 / 18

Implementation of the forest

Add terms to the transport equations

• MomentumFf ,i = −CDafUui

• Potential temperatureSh = ∂

∂z(Qhexp(−γAc))

Ac =∫h

zaf dz

Model by: Schumann and Shaw, 1992

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Implementation of the forest

0 0.1 0.2 0.3 0.4

af

0

0.2

0.4

0.6

0.8

1

z/h

Model by: Lalic and Mihailovic, 2003

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Validation

Before After

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Validation

Sweden

Ryningsnas

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Validation

Precursor:• Homogeneous forest

• Sample inlet data

1st Simulaton:

Add clearing in forest

Investigate flow field

2nd Simulaton:

Add wind turbines

Investigate effect on wind turbines

3rd Simulaton:

Add complex terrain

Investigate effect on wind turbines

Johanna Matsfelt 2017-04-04 10 / 18

Validation

Precursor:• Homogeneous forest

• Sample inlet data

1st Simulaton:

• Add clearing in forest

• Investigate flow field

2nd Simulaton:

Add wind turbines

Investigate effect on wind turbines

3rd Simulaton:

Add complex terrain

Investigate effect on wind turbines

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Validation

Streamlines of time averaged velocity

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Validation

Precursor:• Homogeneous forest

• Sample inlet data

1st Simulaton:

• Add clearing in forest

• Investigate flow field

2nd Simulaton:

Add wind turbines

Investigate effect on wind turbines

3rd Simulaton:

Add complex terrain

Investigate effect on wind turbines

Johanna Matsfelt 2017-04-04 13 / 18

Validation

Precursor:• Homogeneous forest

• Sample inlet data

1st Simulaton:

• Add clearing in forest

• Investigate flow field

2nd Simulaton:

• Add wind turbines

• Investigate effect on wind turbines

Johanna Matsfelt 2017-04-04 14 / 18

Validation

Precursor:• Homogeneous forest

• Sample inlet data

1st Simulaton:

• Add clearing in forest

• Investigate flow field

2nd Simulaton:

• Add wind turbines

• Investigate effect on wind turbines

3rd Simulaton:

• Add complex terrain

• Investigate effect on wind turbines

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Validation

RyningsnasTopology surface

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Validation

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Test cases

Testsite A:

Testsite B:

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Test cases

Testsite A:

• Met mast data before and after clearing forest

• No wind turbines

Testsite B:

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Test cases

Testsite A:

• Met mast data before and after clearing forest

• No wind turbines

Testsite B:

• LiDAR data before and after clearing forest

• Wind turbines

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Thanks for your attention

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