1/2

EllipSys3D large eddy simulation data of single wind turbine wakes in neutral atmospheric conditions

dataset
posted on 08.11.2019 by Paul van der Laan
This data set represents transient velocity fields obtained by large eddy simulations (LES) of a wind turbine wake, for two different ambient turbulence intensities (4% and 12.8%). EllipSy3D [1-3], the in-house flow solver of DTU Wind Energy, is used to compute the LES data. The complete setup and post processed data are described in:

http://onlinelibrary.wiley.com/doi/10.1002/we.1736/pdf
http://iopscience.iop.org/article/10.1088/1742-6596/1037/7/072001/pdf

The average flow field is published as Cases 5 and 6 in the first article, corresponding to a low and high ambient turbulence intensity. Two additional LES data sets are added (*_NoAD_*.nc), where the wind turbine model is switched off so one can isolate the wake effect.

More specific info:
- The NREL-5MW rotor is modeled as an actuator disk with a fixed force distribution that does not change with time. The force distribution is based on a rotor resolved detached eddy simulation. The rotor diameter D is 126 m.
- The coordinate system is: x=streamwise, y=lateral and z=height.
- The LES data is extracted from a plane at hub height (z=90 m) with:
a) Spatial dimensions x=-1D,8.5D and y=-2D,2D (actuator disk is located at (x,y,z) = (0, 0, 90) m,
b) Spatial sample resolution is D/30 (4.2 m). The numerical grid is twice as fine (D/60).
c) Temporal sample resolution is 0.24 s.
d) Each plane has 286x121 = 34606 spatial points.
e) 15500 planes are stored per case.
- The averaged freestream hub height velocity is close to 8 m/s.
- Inflow turbulence is modeled by the Mann model.
- Each case corresponds to 1 hour LES. This duration is long enough to get converged mean velocity fields for the low ambient turbulence case. However, the high ambient turbulence case could be improved by running a longer LES because the mean streamwise velocity field in the far wake is still asymmetric, where a symmetric mean streamwise velocity field would be expected.
- The filenames *_UWV_* should have been called *_UVW_*.

An example Python script, read_netcfd_and_plot.py, is provided which can read and plot the LES data.

For questions, please contact: Paul van der Laan, plaa@dtu.dk

EllipSys3D references:

1: Michelsen, J. A., Basis3D - a Platform for Development of Multiblock PDE Solvers, AFM 92-05, Department of Fluid Mechanics, Technical University of Denmark, December 1994.
2: Michelsen, J. A., Block structured Multigrid solution of 2D and 3D Elliptic PDEs, AFM 94-06, Department of Fluid Mechanics, Technical University of Denmark, May 1994.
3: Sørensen, N. N., General Purpose Flow Solver Applied to Flow Over Hills, Risø-R-827, Risø National Laboratory, Roskilde, Denmark, 1995.

Funding

Danish Council for Strategic Research, grant number 09-067216

History

Related publications (DOI or link to DTU Orbit, DTU Findit)

Topic

  • Wind power plant;>Wind farm;>Wakes

Models

  • Flow;>LES

Activities

  • Modeling

External conditions

  • Terrain type;>Flat

Data category

  • Meteorological data

Licence

Exports

Logo branding

Licence

Exports