A finite element analysis of the hydrodynamic performance of 3- and 4-Fin surfboard configurations

Abstract

This study investigates the hydrodynamic performance of three and four fin surfboard configurations using the CFD/CFX approach. CFD models of three and four fin configurations were setup inside a rectangular domain using CFX meshing. Comparisons of performance were evaluated by analysing both lift and drag coefficients for each fin system as a function of the angle of incidence at various speeds. The 2-equation k-epsilon (k-ε) turbulence model was used as the base for simulations of flow velocities of 3, 5, 7 and 10 m/s. In addition the 7-equation Reynolds stress (RSM) turbulence model was also employed for flow velocities of 10 and 25m/s in order to compare the predictions of the k-ε turbulence model. Results demonstrated that the maximum lift for the three fin configuration occurred at a smaller angle of incidence than for the four fin design. However, the magnitude of maximum lift was the same for both designs under the operating conditions considered in this study. The results from this investigation imply that if a surfer desires a greater degree of manoeuvrability (ideal in regular surfing), then the three fin configuration would be more appropriate in comparison to the four fin configuration. This is because the three fin design is more efficient at generating lift during smaller angles of attack compared to the four fin design. However if stability and speed in the surfboard is preferred (favourable in big wave surfing), then the four fin configuration would be more suitable owing to less lift and drag at smaller incidence angles.