Correction of sidewall blockage effect for twin-rotor vertical axis tidal stream turbine subjected to different solidities

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(3)

Published: March 1, 2025

This study investigates the impact of sidewall blockage effect on hydrodynamic performance twin-rotor vertical axis tidal stream turbine (TR-VATST) with varying solidities. A analysis model for TR-VATST under is developed using computational fluid dynamics. The characteristics in an unsteady flow field are numerically simulated, focusing influence energy extraction efficiency across different tip speed ratios and Base these analysis, a modified applicable to proposed. results indicate that: (1) mean power coefficient increases ratio solidities, improvement faster at higher solidity; (2) as increases, intensifies, leading increase velocity near blades, thereby enhancing from incoming improving coefficient; (3) accurately predict within specific range ratios, ratios. Moreover, effectively eliminates laboratory flume sidewalls, enabling correction experimental reflect offshore prototype unbounded environment. These findings provide valuable engineering insights prediction optimization systems.

Language: Английский

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Hydrodynamic performance of a horizontal-axis tidal turbine subjected to terrain-induced turbulence using the lattice Boltzmann method

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(3)

Published: March 1, 2025

The seafloor's uneven terrain induces turbulence, significantly affecting the hydrodynamic performance and wake dynamics of horizontal-axis tidal turbines (HATTs). A numerical method (LBM-LES) was developed by coupling lattice Boltzmann (LBM) with large eddy simulation (LES) to analyze HATT hydrodynamics. method's validity verified comparing simulations experimental data. detailed analysis then conducted on flow field HATTs installed terrains varying elevations. results reveal that power coefficient (Cp) thrust (Ct) increase exponentially linearly increasing elevation, ranging from 10.2% 58% 6.2% 35.3%, respectively. Moreover, larger features lead more pressure distribution blade surface greater fluctuations in load. Higher also exert a extensive pronounced influence field, inducing shear upstream forming recirculation region downstream. velocity upper increases both downstream, whereas lower experiences significant decrease. flow's recovery rate is faster presence terrain. Additionally, terrain-induced turbulence vortex formation, alters helical structure tip vortices, causes meandering, which intensifies size.

Language: Английский

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CFD calculations of a hydrokinetic turbine in uniform and sheared inflows

Ocean Engineering, Journal Year: 2025, Volume and Issue: 335, P. 121548 - 121548

Published: June 5, 2025

Language: Английский

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