Steady

Bolund Neutral

Javier Sanz Rodrigo's picture
Submitted by Javier Sanz Rodrigo on May 4, 2015 - 2:30pm

Scope

The benchmark revisits the blind test of 2009 now allowing the participants to optimize their models to obtain the best match to the validation dataset.

Objectives

Test model fine-tuning strategies that will be applied in complex terrain sites. Evaluate turbulence models in a test site with well defined boundary conditions.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench.

Input data

The conditions for simulating the Bolund flow field in neutral conditions are:

Axisymmetric Wake Neutral

Jonathan Naughton's picture
Submitted by Jonathan Naughton on May 4, 2015 - 2:27pm

Scope

The benchmark is open to participants of the Wakebench project using flow models to calculate wind turbine wakes. Completion of the benchmark will demonstrate that a simulation approach is capable of capturing the physics necessary to predict behavior of an isolated wake.

Objectives

Evaluate models using a theoretical solution to assure that they can capture an important component of wind turbine wake flows.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench. In the future it will be open for public access

Input data

The wake profiles being compared should meet the following criteria required for equilibrium similarity:

  • x/θ > 100, and
  • U0δ*/ν > 500

Validation data

The validation exercises to be performed consist of the following comparisons.

  • Demonstrate the wake width grows as x1/3

Note that a is an adjustable parameter that depends on a particular simulation boundary conditions

Infinite Wind Farm Neutral

Simon-Philippe Breton's picture
Submitted by Simon-Philippe ... on May 4, 2015 - 2:16pm

Scope

The benchmark is opened to participants of the Wakebench project using flow models to model wakes of wind turbines aligned in a row in search for an asymptotic deficit state. Two cases are suggested to be modeled:

a) a large (but finite) number of turbines

b) an idealized case with an “infinite” number of turbines, where simulations are made either considering periodic boundary conditions in the streamwise direction, or using analytical models (see e.g. Peña and Rathmann 2013 [1]) to predict the flow in the limit of an infinite number of turbines.

Case a) is compared to case b) to determine how many turbines are needed to reach an asymptotic wake state (and to verify that the same final converged wake state is reached).

Objectives

Completion of the benchmark will inform on the number of turbines necessary for an asymptotic deficit state to be reached (which might depend on the quantity that is analyzed), as well as on the flow characteristics associated to this state. The dependency on the distance between the turbines as well as the ambient level of turbulence intensity will be investigated.

San Gregorio Freeflow

Submitted by Francesco Castellani on May 4, 2015 - 2:13pm

Scope

Participants of the Wakebench projects are invited to join the benchmark for flow models over topography in neutral conditions. Simulations need to be performed to ensure an exhaustive characterization of the wind on the main directions. Reliability of the models will be investigated using the anemometric measurements from the available met-masts.

Objectives

Produce the best estimate of the flow field in neutral conditions above the San Gregorio Magno site for the 240°, 270° and 30° wind directions.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench who has signed the NDA attached to the test case guide.

Input data

The following input data are at disposal for simulating San Gregorio Magno flow field in neutral conditions:

San Gregorio Wakes

Submitted by Francesco Castellani on May 4, 2015 - 1:26pm

Scope

The benchmark is open to the participants of the Wakebench project using flow and wake models for complex terrains. 

Objectives

The main goal of this benchmark is to assess flow and wake models behaviour on a very complex terrain environment.

Simulations need to be performed to ensure an exhaustive characterization of the wind on the main direction sector (270°) for the wind farm sub-cluster T10, T11, T12, T13. Reliability of the models will be investigated using the anemometric and SCADA measurements.

Data Accessibility

Brief description about the accessibility of the data

Input data

The ASTER digital terrain, the roughness model (winter and summer retrieved fromwww.dataforwind.com), as well as the layout of the sub-cluster shall be provided to the participants (the coordinate system used is UTM-WGS84-33N).

The wind turbines are Siemens SWT-93 with a nominal power of 2300 kW and a hub height of 80 m; the nominal thrust and power curves shall be available.

The conditions for simulating the wind farm flow are the anemometric conditions at reference met-mast position at hub-height.

 

Mean velocity at hub height (80 m) at met-mast position:         from 5 to 9 m/s

Mean direction at hub height (80 m) at met-mast position:       from 260 to 280°

Askervein Neutral

Javier Sanz Rodrigo's picture
Submitted by Javier Sanz Rodrigo on April 30, 2015 - 4:28pm

Scope

The benchmark is open to participants of the Wakebench project using flow models over topography in neutral conditions. The study will show the changes in the mean flow field above the Askervein hill for different incident flow angles defined by the following wind directions:

  • 210º, perpendicular to the long axis of the hill (classical reference),
  • 130º, parallel to the long axis, and
  • 90º, in the wake of upstream hills.

Objectives

Test model fine-tuning strategies that will be applied in complex terrain sites. Evaluate turbulence models in a test site with reasonably well defined boundary conditions. Evaluate the ability of the models to predict wind direction variations close to the ground induced by local topography.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench.

Input data

The conditions for simulating the Askervein flow field in neutral conditions are:

Alaiz Neutral

Javier Sanz Rodrigo's picture
Submitted by Javier Sanz Rodrigo on March 31, 2015 - 9:14am

Scope

The benchmark is open to participants of the Wakebench project using flow models over topography in neutral conditions. This benchmark is a follow up of the sensitivity analysis (Alaiz_Sensitivity) to validate the results in neutral conditions.

Objectives

Produce the best estimate of the flow field in neutral conditions above the Alaiz site for the North and South wind directions.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench who has signed the NDA attached to the test case guide.

Input data

The conditions for simulating the Alaiz flow field in neutral conditions are: