Study on the enhancement of wave energy capture performance of Savonius hydrokinetic turbines using rear-mounted curved deflectors

Abstract

Savonius-type hydrokinetic turbines (SHTs), recognized for their self-starting capability and structural simplicity, have recently been explored as candidates for wave energy conversion (WEC). However, their inherently low energy capture efficiency (ECE) remains a significant barrier to practical application. To address this challenge, a rear-mounted curved deflector—specifically designed to accommodate the circular or elliptical trajectories of wave-induced flows—was investigated for its potential to enhance SHT performance in complex wave environments. A combination of wave flume experiments and computational fluid dynamics (CFD) simulations was employed to systematically assess the influence of deflector parameters, including horizontal offset (x/D), vertical submergence (y/D), and coverage angle (0°–72°), on flow modulation and turbine torque. Results indicate that the rear-mounted deflector increases the maximum energy conversion efficiency by 31.7% across a range of wave conditions, demonstrating robust adaptability. Mechanistic analysis further reveals that maintaining the integrity of the terminal deflector section is essential for sustaining Venturi-induced pressure gains and reverse vortex shielding. These findings not only demonstrate the effectiveness of rear-mounted deflector configurations but also provide practical design guidance, supporting the advancement of SHTs as a promising new approach to wave energy conversion.