The Computational Fluid Dynamics (CFD) analysis of fluid driven machines for ocean wave energy conversion is an important activity to evaluate failure scenarios of a particular device and to estimate its efficiency. Among the CFD techniques, the SPH numerical method is particularly suitable for the simulation of ocean waves and water turbines with free surface flows.

The present study introduces new features to the SPHERA code (2022, [1]) for the simulation of linear ocean wave propagation, transported wave power, and wave-structure interactions in the presence of floating solid bodies with complex geometry and thin-walled wave generators. These are two conservative, consistent and stable numerical schemes (SPH-ALE3-LCm,pC0 and SPH-ALE3-LCmC1) and the extension of the solid body scheme to structures with complex geometry of any shape.

Validations are obtained by comparison with laboratory experiments and exact closed-form solutions. Negligible errors are obtained for the angular momentum and velocity of a spherical Couette flow, as well as improvements in the estimation of the pressure on solid surfaces compared to a traditional SPH scheme. The error in the specific power of sea waves is +12% compared to -84% for a traditional SPH scheme. The mean gross error of the torque exerted by a periodic sea wave on a scaled boat is 11.2%, similar to the performance of a state-of-the-art SPH model (12.7%), but here obtained by reducing the number of computational nodes around the boat by a factor of 27. A demonstration simulation of the WAVESAX marine energy device (RSE SpA) is also reported.

A new version of the SPHERA code v.10.0.0 (RSE SpA) has been produced, with help, tutorials and ancillary software tools, available for free on github.com as FOSS (Free & Open-Source Software). Numerical simulations performed through the SPHERA code (2022, [1]) used hours of computation provided by HPC (high performance computing) projects. These instrumental resources were obtained through ISCRA competitive national calls for research activities.