Wind Modeling in Mountains: Intercomparison and Validation of Models

摘要

At the Gutsch site near Andermatt the world's highest located large (800 kW) wind turbine is operational since summer 2002 at an altitude of 2350 m a.s.l. For this site a case study was performed to evaluate different types of wind assessment methodologies in complex, mountainous terrain. SODAR (SOund Detection And Ranging) measurements were carried out and showed that vertical wind profiles in complex terrain vary significantly with wind direction and wind speed and do not generally follow an exponential curve. WAsP modeling, Computational Fluid Dynamics (CFD) modeling with CFX-4 (AEA Technology), and CFD modeling with WindSim (VECTOR AS) were performed. WAsP results did not reproduce wind conditions. Instead, WAsP wind profiles followed an exponential curve as is often found in flat terrain. CFD modeling reproduced vertical wind profiles measured by SODAR very well but the modeling procedure is tricky. It is concluded that CFD modeling is adequate for complex terrain but expert modeling and meteorological knowledge is required and results should be validated by measurements. On-site measurements are still essential.