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Submitted by Christian Wetzel on June 11, 2018 - 11:38am
Main hypothesis

FITNAH (Flow over Irregular Terrain with Natural and Anthropogenic Heat sources) has been developed mainly at the Leibniz Universität Hannover, Germany as a mesoscale model. It is applied in the area of wind energy, urban climate and environmental meteorology. For about twenty years FITNAH is used for wind energy site assessment and wind potential mapping by GEO-NET Umweltconsulting GmbH.

hGAST v1

Submitted by Marinos Manolesos on August 26, 2015 - 5:47pm
Main hypothesis
hGAST is an advanced, nonlinear hydro-servo-aero-elastic simulator for WTs. It performs time domain simulations, modal analysis as well as stability analysis. The structure (blades, shaft, tower and support structure) is divided into a number of interconnected bodies and sub-bodies based on the multi-body formulation. Each deformable body is modeled as a Timoshenko beam subjected to combined bending in 2 directions including shear, torsion and extension and solved using the FEM. A dynamic mooring line model defines the mooring contribution based on nonlinear, co-rotational truss elements following the FEM context. The floater is either modeled as a rigid body or as a multi-membered FEM structure. The aerodynamic loads are estimated either using the standard BEM method including corrections and add-on's or the 3D free wake vortex particle method GenUVP. Both methods apply the ONERA dynamic stall model. The hydrodynamic loads are estimated either using potential theory (linear and Newman's approximation) or Morison's equation.


Submitted by Jose Azcona Arm... on June 24, 2015 - 12:37pm
Main hypothesis
CENER has expanded the FAST code by including their own modules as OPASS, for the simulation of mooring line dynamics, DYSTool, for the unsteady aerodynamics modeling or HydroVisc for the inclusion of viscous effects on submerged elements.


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.

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.