Experimental investigation of hydroelastic response and resonance characteristics in Anaconda wave energy converter

The Anaconda wave energy converter (WEC) is a novel category within flexible material WECs. Its simple structural design, ease of transportation and installation, and adaptability to diverse sea conditions have attracted significant attention. Although previous studies have included several wave tank experiments and numerical analyses on the Anaconda WEC, a systematic investigation of its hydroelatic response under different configurations is still lacking. To address this gap, a series of wave tank tests were conducted at the Kelvin Hydrodynamics Laboratory in the United Kingdom using five scaled physical models with variations in tube geometry, material properties, excess pressure, and power take-off (PTO) damping. Measurements of tube deformation and PTO response were employed to evaluate the device's hydroelastic performance. The results reveal that resonance occurs not only when the external water wave phase speed aligns with the free bulge wave speed inside tube, but also at the natural frequencies associated to the tube's heave and surge motions, as well as the PTO dynamics. Tube stiffness, geometry, and excess pressure emerged as critical factors influencing these resonant conditions, while increases in PTO damping and wave amplitude further amplified the response and energy capture. Moreover, the spatial deformation of the tube displayed distinct modal patterns under different resonant conditions. These findings provide essential insights into the hydroelastic behaviour of flexible WECs, laying a robust foundation for optimizing design and validating future numerical models.