Analysis of long distance wakes behind a row of turbines – a parameter study

• Large Eddy Simulations (LES) of the long distance wake behind a row of 10 turbines are conducted to predict wake recovery. The Navier-Stokes solver EllipSys3D is used in combination with the actuator disc concept. Neutral atmospheric conditions are assumed in combination with synthetic turbulence using the Mann method. Both the wind shear profile and turbulence are introduced into the flow field using body forces. Previous simulations using the same simulation method to model the Horns Rev wind farm showed a higher wake recovery at long distances compared to measurements. The current study investigates further the sensitivity to parameters such as the grid resolution, Reynolds number, the turbulence characteristics as well as the impact of using different internal turbine spacings. The clearest impact on the recovery behind the farm could be seen from the background turbulence. The impact of the wind shear on the turbulence level in the domain needs further studies. A lower turbulence level gives lower wake recovery as expected. A lower wake recovery can also be seen for a higher grid resolution. The Reynolds number, apart from when using a very low value, has a small impact on the result. The variation of the internal spacing is seen to have a relatively minor impact on the farm wake recovery.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

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