The study aims at simulating the experiment performed by F.X. Caradonna and C. Tung in 1981 on a model scale rotor. The setup is a rotor made of 2 rectangular, untwisted and untapered NACA0012 rigid blades. These blades are mounted on a tall column containing a drive shaft. During the experiment, pressure distributions and tip vortices are measured, at various rotational speeds and blade pitch angles.
The simulation was performed using FINE™/Turbo software suite from NUMECA. A high quality multi-block structured mesh was generated using AutoGridv5™. The periodicity of the configuration was used and only a sector of 180° was meshed. As the geometrical details close to blade root were not known, a fictive hub was used.
Three key data were analyzed: thrust, pressure load on the blades and tip vortex position.
Results have demonstrated a good agreement with experimental data : pressure coefficients and tip vortex position are well predicted by the simulation.
The above pictures show : the experimental setup, the pressure distribution on the blades, an iso-surface of vorticity and a comparison of FINE™/Turbo results with experiments, for the pressure coefficient at 50% and 80% span height.