Numerical modeling and geometrical investigation of oscillating water column device into a full-scale wave flume and considering savonius turbine insertion

• A new computational model for simulation of OWC device with turbine was developed. • A Savonius turbine was inserted in the exhalation/inhalation duct of OWC device. • Constructal design guided the influence of device geometry on its performance. • New insights about the operation and design of the coupled system was obtained. • The height/length ratio of the chamber strongly influenced the turbine performance. The present work aims to develop a computational method for simulating a full-scale oscillating water column (OWC) device connected to a wave channel, which considers a Savonius turbine inserted in the exhalation/inhalation duct. This model is used to achieve recommendations about the device design and its influence on performance indicators such as turbine and available power ( P turbRMS and P pneuRMS ), and performance coefficient ( C PRMS ). The geometrical investigation is guided by the constructal design. It is considered a turbulent, incompressible, multiphase (air and water) flow simulating the wave flume, the interaction between the wave and the OWC chamber, and the oscillating airflow impinging on the rotational Savonius turbine. The solution is based on the finite volume method (FVM), and the volume of fluid (VOF) is used to treat the multiphase flow. The classical modeling with k – ω shear stress transport (SST) is adopted to model turbulence. Results demonstrated that the coupling with the turbine led to a comprehensive maximum magnitude of C PRMS = 0.2727, like previous literature recommendations for turbines in open channels. The wave flow and hydropneumatic effect on the device were not influenced by the turbine for the present conditions. Despite that, the magnitude of P pneuRMS had a step increase. For example, the optimal configuration resulted in P pneuRMS = 663.96 W and 331.57 W for cases with and without the turbine, respectively. Moreover, the optimal configuration resulted in P turbRMS = 179.24 W, a magnitude twenty-eight times superior to the worst configuration, showing the importance of design in this problem.