Multiple wake

WakeBlaster 2.0

Submitted by Wolfgang Schlez... on May 2, 2017 - 6:52pm
Main hypothesis

ProPlanEn developed this solver specifically for modelling the waked flow in wind farms.  WakeBlaster is a clould based calculation engine offered as SaaS. The software focuses on accurate modelling of the most important aspects of a wind turbine wake.  WakeBlaster's balance between computational performance and accuracy is targeted at industry users. As a 3D RANS solver it is modelling wake-wake and wake-ground interaction that is not well captured by current industry models. WakeBlaster is suitable for wind farms with a few to thousands  of turbines. WakeBlaster 2 refines modelling the waked flow under different stability conditions - now characterised by a flow case specific Monin-Obukhov Length.

DAVM EV

Nicholas Robinson's picture
Submitted by Nicholas Robinson on May 12, 2016 - 4:09pm
Main hypothesis

Uses maximum of eddy-viscosity wake model and a boundary layer wake model at each turbine for each case or timestep.

CFDWind1.1

Submitted by Roberto A. Chav... on May 27, 2015 - 12:00am
Main hypothesis

This model is formulated with the assumptions of isotropic eddy-viscosity turbulence and the k-ε two-equation closure scheme modified for atmospheric flows.

CFDWind1 deals with surface boundary layer (SBL) by imposing a set of coefficients as well as proper modifications to the boundary conditions (inlet boundary and wall functions) in order to comply with the Monin-Obukhov Similarity Theory (MOST) as proposed by Richards & Hoxey (1993) and Parente et al. (2011). 

flapFOAM RANS

Submitted by Jonas Schmidt on May 5, 2015 - 10:53am
Main hypothesis

12 RANS simulations of a uniform non-rotating actuator disk were carried out using OpenFOAM version 2.1.1, with k-e turbulence model including additional dissipation near the rotor, a la El-Kasmi and Masson 2008. These 12 simulations form a data base, from which the wake deficit data is interpolated at arbitrary inflow velocities at hub height. This way CFD simulations are used to define a numerical wake model. flapFOAM is a new wind farm modelling software that is currently in development at Fraunhofer IWES.

SemiParabollicFOAM

Daniel Cabezon's picture
Submitted by Daniel Cabezon on May 5, 2015 - 9:59am
Main hypothesis

The model derives from a previous elliptic model and it is inspired on the parabolic technique of other models such as UPMPARK and Windfarmer but using the actuator disk technique to represent the wind turbine instead of wind speed deficit. 

The wind turbine is represented as an actuator disk uniformly loaded. This means that the wind turbine acts as a sink of momentum, associated to the drag force exerted over the incoming flow. The reference wind speed for each disk is initially calculated from the wind speed at the position of the disk and corrected through the method proposed by Calaf et.al.

The solution algorithm consists of a decomposition of the domain into a finite number of adjacent subdomains that are solved sequentially in the axial direction, using the output of each subdomain as input for the next one. This is done until the end of the domain is reached. This way the computational time becomes significantly lower in comparison to the solution of a single domain by means of a purely elliptic approach.

VestasFOAM 1.1.0 - LES/DES

Submitted by Yavor Hristov on May 5, 2015 - 12:00am
Main hypothesis

VestasFOAM 1.1.0 - DES is built upon the pimpleFoam solver packaged within the publically available OpenFOAM distribution [1]. The k-omega SST DES [2] turbulence model has been implemented in-house. If desired buoyancy can be selected through the Boussinesq approximation.

VestasFOAM - DES is used operationally to determine probability density functions of wind veer and wind shear and compliance with IEC standards for class A,B and C sites. This has been done with good success both forensically (i.e. once problems have been detected on old sites) and during the initial micro-siting activities when transient flow suspicions are raised on prospective sites.

VestasFOAM 1.1.0 - LES is built upon the SOWFA project led by NREL [3]. The SOWFA code has been modularized to fit within the VestasFOAM automated CFD workflows and linked to Vestas turbine libraries for efficient/automated case setup, execution and post-processing. Currently this is only valid on flat terrain/offshore.

For both LES/DES, grids are automatically generated in Pointwise [4] using a structured hyperbolic extrusion. Great care is taken to control grid quality, with small expansion ratios from terrain to rotor bottom, and uniform grid spacing through the turbine/wake areas. As with our steady process, when sufficiently vertically distanced from turbines, the horizontal mesh resolution is continually reduced in order to lower mesh size.

SOWFA - LES

Submitted by Matthew Churchfield on May 4, 2015 - 6:36pm
Main hypothesis

The large-eddy simulation (LES) solver within the Simulator for On/Offshore Wind Energy (SOWFA) is built upon the Open-source Field Operations And Manipulations (OpenFOAM) computational fluid dynamics (CFD) toolbox.  The solver is incompressible and uses the unstructured finite-volume formulation.  Buoyancy effects are included through a Boussinesq buoyancy forcing term.  Turbines are modeled with actuator lines.