Single Wake

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:

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:

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