Test of WindSim for the Wind Flow with Recirculation

Sirhowy Valley Experiment• Located at South Wales, UK– Length 1.8km, Depth 200m• Periodic Valley Terrain– Periodic boundary conditions were applied• For Westerly(270 o ) and Easterly(90 o ) Winds• Mason & King (1984), Mason (1987)Korea Institute of Energy Research

Separation and Reattachment PointsKorea Institute of Energy Research

Korea Institute of Energy ResearchSeparation and Reattachment PointsRNG k-e Modified , k-w k-eConstant

Benchmark SoftwareSoftwareTheoryTurbulenceModelWAsP Linear -WindSimCFDk-eModified k-eMeteodyn CFD One-equationCommentsEasy & FastWell known to WE industryAdequate for complex terrainBased on Phoenics, CHAMAdaptive grid generationStability considerationH.G.Kim*CFDk-e, k-w,RNG k-eIn-house code for R&D* H.G. Kim and V.C. Patel (2000) Test of Turbulence Models for Wind Flow over Terrainswith Separation and Recirculation, Boundary-Layer MeteorologyKorea Institute of Energy Research

Terrain Slope (deg)U/Us @ 8m a.g.l.Elevation (m)Elevation (m)Easterly Wind Case1.51.2510.750.50.257006005004003000-0.25-0.5-500 0 500 1000 1500 20002001000Horizontal Distance (m)WAsP Meteodyn Field Data HGKim WindSim Elevation403020100-500 0 500 1000 1500 20005004003002001000Terrain SlopeElevationKorea Institute of Energy Research

U/Us @ 8m a.g.l.Elevation (m)Westerly Wind Case1.51.2510.750.50.257006005004003000-0.25-0.5-500 0 500 1000 1500 20002001000Horizontal Distance (m)WAsP Meteodyn WindSim Elevation• Separation is expected over terrain slope 15 deg. (Wood, 1995)• What else can we consider?Transient Flow, Three-dimensional effect, Periodic boundary conditions, etc.Korea Institute of Energy Research

Conclusions• WAsP does not predict recirculationWAsP is really a linear model (W = E)• Meteodyn neither predict recirculationquite similar to WAsP prediction• WindSim seems to be more improvedRNG k-epsilon model is recommendedTransient simulation may be necessaryKorea Institute of Energy Research

Auto-Validation of Micrositing at theAntarctic King Sejong StationWindSim User Meeting 2007June 21-22, Tonsberg, NorwayKorea Institute of Energy ResearchDr. Hyun-Goo Kim

Korea Institute of Energy ResearchKing George Island

Korea Institute of Energy ResearchKing Sejong StationSensorsW=15mL=35mD=50mH=5ms=7md=20mh=15m

Building Effects• CFD experiment to figure out building effectsTwo prevailing wind directions are considered (N, E)• Wind speed change due to domes is negligibleKIER10987654321010987654321010987654321015m a.g.l. (Hub height)7m a.g.l. (Sensor height) 2m a.g.l. (Ground level)Korea Institute of Energy Research

Korea Institute of Energy ResearchAuto-Validation1514500040003000KIERKMA200010002000 3000 4000 5000 600050005000400040003000300020002000100010002000 3000 4000 5000 60002000 3000 4000 5000 6000WAsP (KMA) Meteodyn (KMA) WindSim (KMA)131211109876543210500050005000400040004000KIER1.42KIER1.45KMAKMA3000300030001.012000200020001000100010002000 3000 4000 5000 60002000 3000 4000 5000 60002000 3000 4000 5000 6000WAsP (KMA-KIER) Meteodyn (KIER-KMA) WindSim (KMA-KIER)1.51.41.31.21.110.90.80.70.60.50.40.30.20.10

TMY (m)TMY (m)Korea Institute of Energy ResearchEffect of Complex TerrainKMA5500KIER500045004000350030002500200015001000MASTKIERSlope > 15 oMarian Cove2000 2500 3000 3500 4000 4500 5000 5500 6000 6500TMX (m)King George IslandMeanWindSpeed(m/s)Acceleration and direction change / Retardation due to steep hill at the back20191817161514131211109876543210

Conclusions• Auto-validation of wind mappingKMA prediction vs. KIER predictionIdeally, two predictions are supposed to be identical• RMSE errors of wind speed predictionWAsP 0.64 m/s (21% larger than WindSim)Meteodyn 0.89 m/s (68% larger than WindSim)WindSim 0.53 m/s• WindSim won the minimal error prize!Korea Institute of Energy Research

For Tecplot Users• Data conversion program for Tecplot, phi2tec.fD:\WindSim\Project\windfield\unzip 090.phi.Z and 090.xyz.Zconvert Pheonics format → Tecplot formatEmail me if you need, hyungoo@kier.re.krKorea Institute of Energy Research

Korea Institute of Energy ResearchThank youhyungoo@kier.re.krhttp://windenergy.kier.re.kr/hyungoo