Fluid–structure interaction of a flexible rotor in water

In this study, a moderately flexible rotor is investigated experimentally in water channel. The consists of single blade with simplified rectangular geometry and tested various pitch angles at different rotational speeds. flapwise bending deformation induced torsion the are measured using image processing tools, flow fields extracted Particle Image Velocimetry. behaviour depends strongly on angle, it includes extreme downstream upstream for high negative positive pitch, respectively. addition, large-amplitude, low-frequency fluctuations observed certain range speeds pitch. wake vorticity show large-scale recirculation zones being formed intermittently shed behind rotor, resembling dynamics Vortex Ring State known from helicopter aerodynamics. A comparison generated by rigid same also carried out.