We present Large-Eddy Simulations (LES) of a weakly separated diffuser. The influence of mesh resolution and the choice of subgrid model is investigated. Three resolutions ranging from 1.5 to 6.5 million cells are computed. The influence of the subgrid model is studied on the coarsest mesh using no subgrid model, the standard Smagorinsky model, the dynamic Smagorinsky model and the dynamic loca...

Renewable energy is the cornerstone of preventing dangerous climate change whilst maintaining a robust energy supply. Tidal energy will arguably play a critical role in the renewable energy portfolio as it is both predictable and reliable, and can be put in place across the globe. However, installation may impact the local and regional ecology via changes in tidal dynamics, sediment transport p...

Free stream tidal turbines are a source of growing interest in the marine renewable energy field. Some designs that use an actuated mechanism to control individual blade pitch, as the tidal current varies and even during a revolutionary cycle, face the challenge of ensuring high reliability under the loads imposed on the device in the harsh sub sea environment. Adaptive materials have been used...

Tidal energy is a very rich Marine resource, which has high concentration, small geometric scale and strong predictability. The research status, development utilization of tidal current turbine at home abroad are expatiated, two methods for hydrodynamic characteristics turbine, including numerical calculation simulation experiment, introduced, certain significance to the performance optimizatio...

Introduction Reference Model #1 is a tidal turbine operating in a narrow, tidal channel. The site is a generalized version of Tacoma Narrows, Puget Sound, Washington. The resource is a mixed, mainly semidiurnal tidal regime with two ebbs and floods each day of unequal strength (i.e., a diurnal inequality in which a strong ebb/flood exchange is followed by a weak exchange). The diurnal inequalit...

The long-term reliability of tidal turbines is critical if these structures are to be cost effective. Optimized design requires a combination of material durability models and structural analyses. Composites are a natural choice for turbine blades, but there are few data available to predict material behaviour under coupled environmental and cycling loading. The present study addresses this pro...

Reference Model #1 is a tidal turbine operating in a narrow, tidal channel. The site is a generalized version of Tacoma Narrows, Puget Sound, Washington. The resource is a mixed, mainly semidiurnal tidal regime with two ebbs and floods each day of unequal strength (i.e., a diurnal inequality in which a strong ebb/flood exchange is followed by a weak exchange). The diurnal inequalities provide e...

This paper describes the structural design of a tidal turbine composite blade. The structural design is preceded by two steps: hydrodynamic design and determination of extreme loads. The hydrodynamic design provides the blade external shape, i.e. the chord and twist distributions along the blade, which result in optimal performance of the tidal turbine over its lifetime. The extreme loads, i.e....