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Design, Simulation, and Experimental Results for Flexible Rotors in a Ship Airwake

Published Online:https://doi.org/10.2514/1.C033322

First, an overview of the design and construction of a 1/12th Froude-scaled flap-articulated rotor system that is immersed in a ship airwake flowfield is presented. Experimental challenges that were identified during and following the use of this system in an experimental study and their impact on the data are discussed. The experimental rotor system is presented as a useful testbed for theories and models of flexible multibody systems with gyrating beams undergoing large deformations. Second, the flap-articulated Froude-scaled experimental rotor system is tested in a scaled ship airwake environment using the National Research Council 2×3m wind tunnel. Based on experimental and simulation data, conclusions are drawn regarding the influence of the aerodynamic environment and the rotor operation parameters on the rotor blade elastic deflections during the engagement/disengagement phase. It is concluded that the parameters of the engagement/disengagement profile play a minimal role in the occurrence of large elastic deflections, known as the blade sailing phenomenon. Increasing or decreasing the collective pitch setting along with increasing the wind speed and ship deck roll angle is found to amplify the blade sailing phenomenon. Additionally, it is further verified that, compared to an unsteady aerodynamic model, the nonlinear quasi-steady aerodynamic model with Mach number effects on the stall point is sufficient for blade sailing studies; however, the former is shown to be more accurate, particularly at higher wind speeds. The experimental data are also used to successfully validate developed multibody dynamics tools.

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