Field

Alaiz Sensitivity

Javier Sanz Rodrigo's picture
Submitted by Javier Sanz Rodrigo on May 7, 2015 - 10:22am

Scope

The benchmark is open to participants of the Wakebench project using flow models over topography in neutral conditions. This initial benchmark will carry out an assessment of the sensitivity to modeling criteria that is adopted when approaching the simulation of a realistic site for wind farms in complex terrain. In order to simplify the analysis, only the North and South wind direction sectors will be analyzed.

Objectives

Carry out sensitivity tests on different elements of the modeling chain that require user-dependent decisions: domain dimensions, mesh type and resolution, roughness definition, and wind direction binning (1).

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:

Sexbierum Single Wake Neutral

Submitted by Matthew Churchfield on May 4, 2015 - 4:12pm

Scope

The benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is a realistic wake case measured at the Dutch Experimental Wind Farm at Sexbierum.  It focuses on the single wake case, which is a good “building-block” to the double wake case (Sexbierum_DoubleWakeNeutral).

Objectives

Demonstrate how wake models perform and capture the wake formation and evolution process in the presence of atmospheric shear and turbulence.

Data Accessibility

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

Input data

The conditions for simulating the Sexbierum double wake are:

Sexbierum Double Wake Neutral

Submitted by Matthew Churchfield on May 4, 2015 - 4:10pm

Scope

The benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is a realistic wake case measured at the Dutch Experimental Wind Farm at Sexbierum that has the added complexity of multiple wake interaction. It should test a wake model’s ability to reproduce the wake merging process.

This benchmark follows the single-wake case (Sexbierum_SingleWakeNeutral). Participants are strongly encouraged to participate in both exercises for a more complete model evaluation.

Objectives

Demonstrate how wake models perform and capture the wake merging process in the presence of atmospheric shear and turbulence.

Data Accessibility

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

Input data

The conditions for simulating the Sexbierum double wake are:

Risø Wake Lidar Single Wake

Ewan Machefaux's picture
Submitted by Ewan Machefaux on May 4, 2015 - 4:07pm

Scope

The benchmark is open to participants of WakeBench who want to validate the near-wake models in horizontally homogemeous terrain using lidar cross-sectional scans from 1 to 5 rotor diameter downstream.

Objectives

Determination of mean wake velocity ratio at hub height as function of downstream position for a Nordtank 500 kW stall regulated turbine in flat and horizontally homogeneous terrain at different atmospheric stabilities and wind conditions.

Data Accessibility

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

Input data

The necessary input parameters related to the turbine, the terrain and the ambient flow are:

Norrekaer Enge Data Qualification

Submitted by Kurt Schaldemos... on May 4, 2015 - 4:04pm

Scope

The benchmark is open to participants of Wakebench who want to qualify wind farm measurements for wake model validation.

Objectives

The main objective is to qualify wind farm measurements before data analysis can be performed. The qualification includes an analysis of the wind farm surroundings to identify potential terrain effects and obstacles, which can influence the local flow conditions. The data qualification includes basic quality screening, identification of outliers, and qualification of power values for each wind turbine. This process is used to eliminate sequences where the wind turbines have been stopped or been in an idling mode, start sequence, stop sequence or failure mode.  The data qualification analysis includes to definition of quality-checked references of wind speed and direction.

Data Accessibility

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

Input data

Approximately one year of 10-minute statistics for power and wind measurements recorded in a 42 x 300 kW wind farm have been made available for this benchmark.

The recordings are available in three different formats:

1)       Stored in a MySQL database made accessible through the Internet;
2)       Stored in MS-EXCEL tables or
3)       Stored in a MS-DBASE database.

Norrekaer Enge Power Deficit 1

Submitted by Kurt Schaldemos... on May 4, 2015 - 4:02pm

Scope

The benchmark is open to participants of Wakebench who want to analyze wind farm measurements for wake model validation.

Objectives

Determination of power deficit between pairs of turbines in the wind farm as function of flow direction.

Data Accessibility

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

Input data

Approximately one year of 10-minute statistics for power and wind measurements recorded in a 42 x 300 kW wind farm have been made available for this benchmark.

Validation data

  1. Determine the power deficit between a pair of wind turbines with 6.3 D spacing for a 20 deg inflow sector. The deficit between turbines A2 and A1 is determined for the inflow sector 155-175 deg for a 5° moving window and wind speed interval of 6 – 12 m/s with reference to M1. Power deficit = 1 - Power(A2)/Power(A1)

Model runs

Not applicable 

Norrekaer Enge Power Deficit 2

Submitted by Kurt Schaldemos... on May 4, 2015 - 4:00pm

Scope

The benchmark is open to participants of Wakebench who want to analyze wind farm measurements for wake model validation. 

Objectives

is to determine power deficit along straight rows of turbines in the wind farm. The turbines in flow sector 165 deg  has a constant spacing of 6.3D, while the spacing in direction 257 deg is constant and equal to 8.2D except for a large gap of 26.7D where speed recovery is to be expected.

Data Accessibility

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

Input data

Approximately one year of 10-minute statistics for power and wind measurements recorded in a 42 x 300 kW wind farm have been made available for this benchmark. The following inflow conditions will be considered:

  • Wind speed interval: 9 – 11 m/s;
  • Turbulence intensity: all
  • Flow sectors: 155-175º and 247-267º

Validation data

  1. Power deficit along 6 distinct rows (A, B, C, D, E & F) determined as function of spacing for a direction of 165º with reference to M1.
  2. Power deficit along 7 distinct rows (A1-F1, A2-F2, A3-F3, A4-F4, A5-F5, A6-F6 & A6-F6) determined as function of internal spacing for a direction 257º with reference to M1.

Power deficit = 1 - Power(A2)/Power(A1)

Lillgrund Direction

Submitted by Matthew Churchfield on May 4, 2015 - 3:54pm

Scope

This document outlines three separate components of this benchmark.  It is the hope that the participant will simulate all three components, but the participant is free to simulate any or all of the components.

This benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is based on the actual operational Lillgrund wind farm in which there are multiple turbines interacting within an array.  The benchmark aims to test a wake/atmospheric model to reproduce the power production observed at Lillgrund when wind is from a southwesterly, southeasterly, and northwesterly sector. 

For the Southwest case, the sector is centered upon 222° aligned with rows A-H in which there is 4.3 rotor diameter (D) spacing.  For the Southeast case, the sector is centered upon 120° aligned with rows 1-8 in which there is a 3.3 D spacing.  For the Northwest case, the sector is centered upon the 300° direction aligned again with rows 1-8, with flow coming from the opposite direction of the Southeast case, with a 3.3 D spacing.

Lillgrund 360 Efficiency

Submitted by Matthew Churchfield on May 4, 2015 - 3:12pm

Scope

The benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is a case based on the actual operational Lillgrund wind farm in which there are multiple turbines interacting within an array.  This benchmark aims to test a wake/atmospheric model to reproduce the wind plant efficiency observed at Lillgrund over the full wind rose.

Objectives

Demonstrate how wake models perform and capture the wake formation and merging process in the presence of atmospheric shear and turbulence within a large modern wind farm composed of modern multimegawatt turbines. 

Data Accessibility

Brief description about the accessibility of the data

Input data

The conditions for simulating the Lillgrund_360_Efficiency case are:

Lillgrund TI Spacing

Submitted by Matthew Churchfield on May 4, 2015 - 3:09pm

Scope

The benchmark is open to participants of the Wakebench project using wake and, possibly, atmospheric boundary layer models. This is a case based on the actual operational Lillgrund wind farm in which there are multiple turbines interacting within an array.  This benchmark aims to test a wake/atmospheric model to reproduce the maximum power deficit of the second turbine in a row as a function of spacing and turbulence intensity.

Objectives

Demonstrate how wake models perform and capture the wake formation and merging process in the presence of atmospheric shear and turbulence within a large modern wind farm composed of modern multimegawatt turbines. 

Data Accessibility

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

Input data

The conditions for simulating the LillgrundTISpacing case are: