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Wind Farm Flow Assessment

The EnviroWizard with STAR-CCM+

STAR-CCM+ based Wind Resource Assessment: In Use in Industry Today

Vestas Site Check Tool for Wind Farm Layout Design

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And How Is It Done?

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Two Key Java Macros

An excellent example of customizable STAR-CCM+ (for workflow in any industrial application

In the Background: On the Vestas Central HPC Cluster in Denmark

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Scaling of STAR-CCM+ Application on Vestas Cluster

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The Business Benefit to Vestas

Previous procedure required field engineers to send a request and files to Vestas Headquarters CFD Group for processing:

Average turnaround time to receive necessary 3-D CFD simulation results (data, plots) in standard Vestas report form: 3 weeks

New, automated push-button procedure, embedded into Vestas Site Check:

Now fully deployed (since April 2009) to over 100 Vestas engineers around the world

Average turnaround time from pushing the button to receiving an e-mail with the needed reports: 2 hours

9 A productivity speed-up of 250:1

Accurate Wind Resource Assessment:

Effects of Forest Canopies

Powerful State-of-the-Art Computational Fluid Dynamics (CFD), driven by a wind-farm-specific EnviroWizard GUI, enables highly-automated evaluation of rough terrains with forest canopies to more accurately estimate Annual Electricity Production from proposed wind farms

Forest Modeling

Forest edge = 0.4 roughness

Forest Height = 20m

Porosity Coefficients

Wake Interactions

Modeling the turbine interaction problem can generally be split into two problems

Near Wake Effects 3D effects

Tip effects

Stall

High fidelity models BEM/CFD required

Far wake (Wind Park Level) including Wake interaction

Turbulence modelling

Terrain effects - Lower fidelity model such as actuator

discs can be used

NASA AMES Wind Tunnel

Accurate Wind Resource Assessment: Wake Effects of Multiple Turbines

Powerful State-of-the-Art Computational Fluid Dynamics (CFD), driven by a wind-farm-specific EnviroWizard GUI, enables highly-automated evaluation of very rough terrains and wake effects of multiple turbines to more accurately estimate Annual Electricity Production from proposed wind farms

Multiple Wind Turbine Wakes: Formulation Details

Wake Interactions

The STAR-CCM+ EnviroWizard allows the User to investigate the turbine interaction problem in a quick and efficient manner

Setting up the case automatically

Every direction must be remeshed

Offshore Wind Farm Simulation: Wakes

Askervein Hill

Classic Gaussian Hill Validation Case Research Report, Taylor & Teunissen, MSRB-84-6, 1983

Wind Direction 210

Summary of the Bolund Blind Experiment and CD-adapcos Involvement

Steve Evans and Dennis Nagy February 2010

Most Recent Wind Validation: Bolund Blind Experiment (December 2009)

Conducted by Risoe/DTU in Denmark (sponsored by Vestas A/S)

Measured wind data (4 months) on Bolund Island (near Risoesee two photos below and photo on title slide)

8 measurement mast locations (see middle map below)

52 different models/methods (from different companies and research establishments around the worlde.g., linear, CFD, wind tunnel) were run (using the data from the two leading-edge masts) for Risoe to compare (blind) with their remaining measurements.

CD-adapco submitted CFD runs with STAR-CCM+: Were run during Sept/Oct 09

Results (anonymousgathered and organized by Risoe/DTU) were presented at the Bolund Workshop (Roskilde, Denmark, Dec. 3-4, 2009)

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Bolund Experiment: CD-adapco Participation

Black Crosses - Met Mast locations

Sample Results from Bolund Experiment (239)

Turbulent Kinetic Energy

Pink - STAR-CCM+ RANS Black square Experiment Red/Blue dots Scale Model(tunnel)

General Bolund Workshop Conclusions

Linear models (WAsP-like) are less accurate on complex terrains.

CFD is clearly more accurate. Quoting from the Risoe/DTU presentation: You can get good results with most [CFD] solvers; The user is more important than the solver

i.e., in CD-adapcos opinion, all CFD results were similarly accurate, so the practical issue becomes one of speed, automation, and ease of use

Detailed Wind Flow Around Wind Turbines

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Individual Turbine Wake Turbulence (Animated)

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Pollution Flow in Complex Energy Production Environments