A Wells turbine blade for wave power conversion has hysteretic characteristics in a reciprocating flow. The hysteretic loop is opposite to the well-known dynamic stall of an airfoil. In this paper, the mechanism of the hysteretic behavior was elucidated by an unsteady 3-dimensional Navier-Stokes...

This paper presents the performance of a Wells turbine operating under unsteady bi-directional airflow conditions. In this study, four kinds of blade profile were selected, NACA0020, NACA0015, CA9 and HSIM 15-262123-1576. The experiments have been carried out for two solidities under sinusoidal...

Oscillating Water Column based wave energy plants convert wave energy into low pressure pnuematic power in the form of bi-directional air flows. Air turbines which are capable of rotating uni-directionally in bi-directional air flow, otherwise also known as self-rectifying turbines, are used to...

An experimental study was carried out to develop a new type of two-way diffuser suitable for a fluid flow energy conversion system. It is known that the power available from the fluid flow is proportional to the cube of the free stream velocity of the flow. Therefore, in order to take higher...

The flow through the air turbine of an oscillating water column (OWC) wave energy converter is reciprocating and is random and highly variable. It is not surprising that the time-averaged efficiency of the air turbine is substantially lower than that of a conventional turbine working in nearly...

The paper presents results from model testing of a self-rectifying radial-flow air turbine, that is being developed as an alternative to the axial-flow self-rectifying turbines for applications in wave energy conversion. In the new machine, named biradial turbine, the flow into, and out of, the...

The paper concerns the hydrodynamic analysis and optimization of an OWC spar buoy, possibly the simplest concept for a floating oscillating water column (OWC) wave energy converter. It is an axisymmetric device consisting basically of a submerged vertical tail-tube-fixed to an axisymmetric...

Wells turbine is a self-rectifying airflow turbine capable of converting pneumatic power of the periodically reversing air stream in oscillating water column into mechanical energy. This paper reports the computational analysis on performance and aerodynamics of Wells turbine with the NACA 0021...

In this work an experimental study of flow through a Wells turbine with NACA0015 profiles submitted to an unsteady and bi-directional flow is presented.

The Wells wind turbine, which is used in the oscillating water column wave energy device, is simple but has a low efficiency. It stalls in strong winds caused by large waves and has a subsequent slow recovery. Its close relationship with the vertical axis wind turbine is pointed out. A novel...