This paper deals with the application of Computational Fluid Dynamics (CFD) to the analysis of the aerodynamic characteristics of symmetrical airfoil blades in 2-Dimensional isolated flow. The CFD model was first developed by analysing with different solver parameters and then validating against published experimental results for the NACA 0012 blade profile. The model was solved as compressible flow using a Navier-Stokes solver with transition fixed at 5% of the chordlength. It is shown that the lift forces were predicted accurately and also that significant improvement in drag prediction over previous CFD models was achieved. The validated model was then used to compare different proposed airfoil profiles for the Wells Turbine.
While alternative renewable energy sources, such as solar, wind and conventional water energy, are well researched and developed, the more unconventional wave energy is still being researched. Among the methods being investigated to extract the energy from the waves is the oscillating water column (OWC), which is used in combination with the bi-directional, self-rectifying Wells turbine. The oscillating water column converts the wave motion into an oscillating air stream and the Wells turbine converts this alternating airflow into unidirectional rotation. The Wells turbine is an axial flow turbine essentially consisting of a rotor with radial airfoil blades of symmetrical cross section. The blades are symmetrical about an axis normal to the turbine axis and so are insensitive to the direction of the axial airflow, thus providing the unidirectional torque from the oscillating airflow. Unlike most turbines, which are designed for an optimum operating condition, the Wells Turbine operating conditions are governed by the random nature of the sea, and hence it is important to maximise the range of sea conditions over which it can operate efficiently.
