LES-DES

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.