CFD Studies on Wind Turbines in Complex Terrain under Atmospheric Inflow Conditions

Schulz, Christoph; Klein, Levin; Weihing, Pascal; Lutz, Thorsten; Krämer, Ewald

doi:10.1088/1742-6596/524/1/012134

Cited by 32 publications

(21 citation statements)

References 7 publications

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“…Mountainous terrains can introduce significant horizontal variations in the flow on a large scale, since tall mountains may extend well beyond the reach of the atmospheric boundary layer boundary layer . The presence of a hill or a mountain ridge can also increase the turbulence levels in the flow, yielding higher power and load fluctuations for turbines installed at such sites . The prevailing flow conditions at a complex‐terrain site must therefore be carefully considered in order to avoid errors in the predicted wind‐power availability.…”

Section: Introductionmentioning

confidence: 99%

A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills

2018

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In the present work, the wake development behind small‐scale wind turbines is studied when introducing local topography variations consisting of a series of sinusoidal hills. Additionally, wind‐tunnel tests with homogeneous and sheared turbulent inflows were performed to understand how shear and ambient turbulence influence the results. The scale of the wind‐turbine models was about 1000 times smaller than full‐size turbines, suggesting that the present results should only be qualitatively extrapolated to real‐field scenarios. Wind‐tunnel measurements were made by means of stereoscopic particle image velocimetry to characterize the flow velocity in planes perpendicular to the flow direction. Over flat terrain, the wind‐turbine wake was seen to slowly approach the ground while it propagated downstream. When introducing hilly terrain, the downward wake deflection was enhanced in response to flow variations induced by the hills, and the turbulent kinetic energy content in the wake increased because of the speed‐up seen over the hills. The combined wake observed behind 2 streamwise aligned turbines was more diffused and when introducing hills, it was more prone to deflect towards the ground compared to the wake behind an isolated turbine. Since wake interactions are common at sites with multiple turbines, this suggested that it is important to consider the local hill‐induced velocity variations when onshore wind farms are analysed. Differences in the flow fields were seen when introducing either homogeneous or sheared turbulent inflow conditions, emphasizing the importance of accounting for the prevailing turbulence conditions at a given wind‐farm site to accurately capture the downstream wake development.

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Section: Introductionmentioning

confidence: 99%

A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills

2018

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“…The turbulent velocity field was introduced via body forces in the momentum equation. Schulz et al [22] conducted a DES simulation for wind turbine in both flat and complex terrain to evaluate the influence of inflow turbulence on blade load and power response.…”

Section: Introductionmentioning

confidence: 99%

Coupled multi-body dynamics and CFD for wind turbine simulation including explicit wind turbulence

et al. 2015

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a b s t r a c tA high fidelity approach for wind turbine aero-elastic simulations including explicit representation of the atmospheric wind turbulence is presented. The approach uses a dynamic overset computational fluid dynamics (CFD) code for the aerodynamics coupled with a multi-body dynamics (MBD) code for the motion responses to the aerodynamic loads. Mann's wind turbulence model was implemented into the CFD code as boundary and initial conditions. The wind turbulence model was validated by comparing the theoretical one-point spectrum for the three components of the velocity fluctuations, and by comparing the expected statistics from the CFD simulated wind turbulent field with the explicit wind turbulence inlet boundary from Mann model. Extensive simulations based on the proposed coupled approach were conducted with the conceptual NREL 5-MW offshore wind turbine in an increasing level of complexity, analyzing the turbine behavior as elasticity, wind shear and atmospheric wind turbulence are added to the simulations. Results are compared with the publicly available simulations results from OC3 participants, showing good agreement for the aerodynamic loads and blade tip deflections in time and frequency domains. Wind turbulence/turbine interaction was examined for the wake flow. It was found that explicit turbulence addition results in considerably increased wake diffusion. The coupled CFD/MBD approach can be extended to include multibody models of the shaft, bearings, gearbox and generator, resulting in a promising tool for wind turbine design under complex operational environments.

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“…Hence the blade mesh is the most important key feature in the turbine simulations, one must carefully set the different parameters in the script to insure the quality of the generated mesh. Several CFD simulations of different offshore and onshore wind turbines have been conducted using that process chain at IAG [12], [13] and [14]. These CFD simulations proof the quality of the used process chain at the IAG.…”

Section: Process Chain For Wind Turbine Simulationsmentioning

confidence: 63%

“…The hub rotation is around the rotor axis as defined before at 5 • tilt angle. Finally the blade mesh was generated (blade sectional mesh is shown in Figure 3) using the proven script at the IAG [13] and [15]. 300 cells were used in chord-wise direction and 100 cells in (span-wise) radial direction.…”

Section: Computational Domainmentioning

confidence: 99%

3-D Time-Accurate CFD Simulations of a Multi-Megawatt Slender Bladed HAWT under Yawed Inflow Conditions

Sayed

Lutz

Krämer

2016

J. Phys.: Conf. Ser.

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CFD Studies on Wind Turbines in Complex Terrain under Atmospheric Inflow Conditions

Cited by 32 publications

References 7 publications

A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills

A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills

Coupled multi-body dynamics and CFD for wind turbine simulation including explicit wind turbulence

3-D Time-Accurate CFD Simulations of a Multi-Megawatt Slender Bladed HAWT under Yawed Inflow Conditions

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