Blade performance on the effect of whale wavy leading- edge by using meshfree analysis

Abstract

This study investigates the application of a wavy leading edge (WLE)—based on the flipper of a humpback whale—on a water turbine blade and its effect on blade performance. The analysis was conducted using a numerical tool known as MeshFree. Focusing on the blade application in a water turbine, a wavy leading edge was applied and adapted to the blade due to the proven capability of this feature in reducing turbine cut-in speed. The approach utilises a meshless method (MeshFree), which has been claimed to result in higher accuracy output compared to other well-known numerical tools such as the Finite Difference Method (FDM) and Finite Element Method (FEM). In this study, the subject was considered as a thin-plate element, and the formulation was made in MeshFree, with the processing conducted in MATLAB software. A number of outputs were obtained from the MeshFree method and then applied in a parametric study. A few sets of parameters were identified consisting of radius, number of nodes, and number of Gauss points, where all values were fixed prior to observing the effect of the wavy pattern on the maximum deflection of the blade. Then, the wavelength, amplitude, and curve at the corner of the blade were varied to observe their effect on blade deflection. The results show that the wavelength parameter had no significant effect on the blade deflection compared to the normal design of the blade unlike the amplitude and curve parameters. In sum, although the WLE factors can increase the turbine’s effective energy production, it could also contribute to higher maximum deflection on the blade when amplitude is increased. However, this increment could be controlled by increasing the curve at the corner edge of the blade.