Numerical analysis of a Wells turbine with flexible trailing blade edges

Abstract

This thesis examines the effect of a partially morphing blade on the performance of a Wells turbine, for the purpose of wave energy conversion. A numerical model is constructed using Foam-Extend, v4.0, incorporating a fluid domain as well as a solid region and strongly coupled fluid-structure interaction algorithm. Once the model is validated against previous experimental work, the turbine tip gap and elastic modulus of the solid region are varied, and the resulting performance and flow field changes are examined. Each turbine with morphing blades performed better than its corresponding rigid counterpart, regardless of the degree of flexibility introduced to the blade. A maximum increase in torque output of nearly 17% was observed in some cases, due to the combined effect of blade deformation into the tip gap area as well as axial deformation, resulting in a change of local angle of attack. These increases were largely in part due to the favorable changes in pressure field resulting from the deformation of the blade under inertial and aerodynamic forces.