Session: 09-07-02 Tidal & Current Energy I

Submission Number: 181893

Performance Enhancement for a Vertical Axis Turbine by Blade Design Improvement 

This study presents a comprehensive optimization of the blade geometry for the so-called Vertical Axis Autorotation Current Turbine (VAACT) using Computational Fluid Dynamics (CFD) simulations coupled with a genetic algorithm (GA). The optimization process aimed to minimize the resisting torque produced by the returning blade, the major contributor to performance loss in drag-type vertical axis turbines. A parametric investigation was first conducted to assess the effects of maximum camber and its position on turbine efficiency. Regression surfaces relating the power coefficient to maximum camber (M), camber position (P), and tip speed ratio (TSR) were then generated and used as input for the GA optimization routine. The optimal configuration was obtained for M = 40%, P = 65%, and TSR = 1.05, achieving an efficiency of 40.68%. The optimized blade demonstrated a 21% improvement in performance compared to the conventional S-shaped profile, primarily due to the reduction of resisting torque during the returning phase. The intra-cycle analysis showed that the S-shaped turbine allowed the distribution of drag and lift effects along the cycling, improving efficiency. low field analysis confirmed that the optimized geometry delays vortex shedding and reduces pressure gradients along the returning blade, leading to the improved hydrodynamic behavior. The results demonstrate that GA-driven optimization offers an effective way for the design of vertical-axis hydrokinetic turbines.

Presenting Author: Rodrigo Soares Federal University of Rio de Janeiro

Presenting Author Biography: Rodrigo Soares is a postdoctoral researcher in Ocean Engineering at the Alberto Luiz Coimbra Institute for Graduate Studies and Research in Engineering (COPPE/UFRJ). He holds a degree in Naval Architecture and Ocean Engineering (2021) from the Federal University of Rio de Janeiro (UFRJ), as well as a Masters degree (2022) and a Ph.D. (2025) in Ocean Engineering from COPPE/UFRJ. His academic background includes projects in offshore renewable energy, such as the development of monopile wind turbines for the Brazilian market, floating photovoltaic systems, the dynamic behavior of subsea manifolds during installation, and numerical/experimental studies of hydrokinetic turbines in steady and oscillatory flows. He has practical experience with advanced simulation software, including ANSYS Fluent, OrcaFlex, WAMIT, OrcaWave, and NUMECA. Rodrigo is also a researcher at the Laboratory of Waves and Currents (LOC/COPPE/UFRJ) and at the Ocean Technology Laboratory (LabOceano/COPPE/UFRJ). His scientific contributions include publications in international journals, book chapters, and numerous presentations at major conferences in the fields of ocean energy and offshore engineering. His academic and professional recognitions include the ABS Brazil Award (2021) and the Ozires Silva Award for Sustainable Entrepreneurship (2019). His expertise covers naval architecture and ocean engineering, offshore renewable energy, computational and experimental hydrodynamics, with a strong focus on innovative projects that support the energy transition and maritime sustainability.

Authors:

Rodrigo Soares Federal University of Rio de Janeiro
Antonio Carlos Fernandes Federal University of Rio de Janeiro
Joel Sales Junior Federal University of Rio de Janeiro