Laboratory

Waving Wheat Neutral

Javier Sanz Rodrigo's picture
Submitted by Javier Sanz Rodrigo on May 4, 2015 - 4:13pm

Scope

The benchmark is open to participants of the Wakebench project using canopy models. This is the first element of the building-block approach in this range, so it should be mandatory if you intend to participate with this model in other test cases down the line.

Objectives

Demonstrate the performance of the model at reproducing the mean flow and turbulent quantities of a horizontally-homogeneous canopy profile.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench who agree with the terms and conditions described below.

Input data

The conditions for simulating the waving wheat canopy profile in neutral conditions are:

  • Free-stream wind speed: U0 = 10.2 m/s
  • Canopy height: hc = 0.047 m
  • Canopy drag coefficient: Cd = 0.68
  • Canopy-area-density: A = 0.1 m-1
  • Obukhov length: L0 = ∞
  • Use dry air with a density ρ = 1.225 kg/m3 and dynamic viscosity μ = 1.73e-5 kg/ms

Validation data

The validation consists on mean and standard deviation values for the horizontal wind speed (U) and mean values of the shear stress (uw).

Model runs

The user is free to define the computational domain and model settings that best fit with the validation data.

Furry Hill Neutral

Javier Sanz Rodrigo's picture
Submitted by Javier Sanz Rodrigo on May 4, 2015 - 2:33pm

Scope

The benchmark is open to participants of the Wakebench project using canopy models. The benchmark will evaluate the ability of the models at reproducing the interaction of canopy and hill flows in idealized conditions.

Objectives

Demonstrate the performance of the models at reproducing mean flow and turbulent quantities on a hill-induced heterogeneous canopy. Test model fine-tuning strategies in a controlled environment when boundary conditions are well defined.

Data Accessibility

The benchmark is offered to participants of the IEA Task 31 Wakebench who agree with the terms and conditions described below.

Input data

The conditions for simulating the Furry Hill experiment in neutral conditions are:

  • Inlet profile: measurements at X = -2.125 m (X/L = -5.06)
  • Hill profile: Zh(X)=h/(1+(X/L)2), with X = 0 at the crest of the ridge, truncated at X = ±925 mm where it smoothly meets the flat floor. Ridge height h = 150 mm, half-length L = 420 mm.
  • Canopy height: hc = 0.047 m
  • Canopy drag coefficient: Cd = 0.68
  • Canopy-area-density: A = 0.1 m-1
  • Obukhov length: L0 = ∞
  • Use dry air with a density ρ = 1.225 kg/m3 and dynamic viscosity μ = 1.73e-5 kg/ms

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