Numerical analysis of flexible tube wave energy converter using CFD-FEA method

To better understand the performance of flexible tube wave energy converters (WECs) in ocean waves, a coupled numerical analysis tool based on computational fluid dynamics and a finite element method is employed to perform numerical simulations for the well-known Anaconda WEC under given different regular wave conditions. The nonlinear behaviour of Natural Rubber is considered by using YEOH hyper-elastic model. Fluid-structure interaction responses of the Anaconda WEC are compared considering the impact of incident wave speed on the performance of the device. The free surface around the WEC, internal pressure and velocity in the flexible tube, structure deformation and stress distribution are fully explored. The results show that the proposed numerical analysis tool in this work is able to predict the complex fluid-structure interactions of flexible tube WEC in waves, including wave nonlinearity and inhomogeneous distribution of stress at cross-section. The typical resonant responses are also captured when the incident wave speed matches the bulge wave speed. The internal pressure amplitude, capture width, structural deformation and hoop stress all increase at resonance. Moreover, the deformed shape of the flexible tube is found to depend on the ratio of wavelength to tube length.