![]() The qualification of the ice accretion characteristics for each case was done by performing a 3D scan of the iced wind turbine blade model. Runback towards the trailing edge is observed for the Glaze Ice condition along with the formation of rivulet structures, while most of the ice accretion happens around the leading edge for the Rime Ice condition. A high-speed imaging camera was used to capture the time evolution of the ice accretion process for each case. The test cases were performed at a temperature of T = -5℃ for Glaze Ice and T = -15℃ for Rime ice. Four cases were tested for Glaze and Rime ice conditions each, at LWC = 0.5 g/m3, 1.0 g/m3, 2.0 g/m3, and 4.0 g/m3 with a runtime of t = 600s, 300s, 150s, and 75s respectively to keep the total amount of accreted ice constant. In the present study, an experimental investigation is performed in the Icing Research Tunnel available at the Iowa State University (ISU-IRT) to study the dynamic ice accretion process over a Wind Turbine blade model for high Liquid Water Content (LWC) values. The objective of this study is to replicate the conditions experienced by Offshore Wind Turbines in cold climates that are prone to icing events involving high Liquid Water Contents (LWC) and to study the icing physics surrounding this phenomenon. View Video Presentation: Onshore and Offshore Wind Turbines installed in cold climates experience are subject to icing conditions regularly. Due to the strong reduction of roughness sensitivity the design for inboard airfoils could primarily focus on high lift and structural demands. In particular the change in lift characteristics in the case of leading edge roughness for the 35% and 40% thick DU airfoils, respectively DU 00-W-350 and DU 00-W-401, is remarkable. The RFOIL code is believed to be capable of approximating the rotational effect. At inboard locations the influence of rotation can be significant and 2d wind tunnel tests do not represent the characteristics well. For a 30% thickness the DU 97-W-300 meets the requirements best. For the 25% and 30% thick airfoils the best performing airfoils can be recognized by a restricted upper surface thickness and a S-shaped lower surface for aft-loading. In this paper the performance for the airfoil series DU, FFA, S8xx, AH, Risø and NACA are reviewed. Towards the root structural requirements become more important. ![]() In particular at mid-span aerodynamic requirements dominate, demanding a high lift-to-drag ratio, moderate to high lift and low roughness sensitivity. In modern wind turbine blades airfoils of more than 25% thickness can be found at mid-span and inboard locations.
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