![]() ![]() At this speed, the LR surfboard generally experiences larger pressures and thus higher forces. Minimal differences are noticeable on the 4 m/s case while larger difference can be seen on the 8 m/s case. In Figure 3, the pressure distribution on the middle line of the board for the three boards is plotted. In particular Kramer studied with CFD at 2D flat plate which can be compared with a simplified version of a surfboard, and Oggiano studied and compared a traditional alaia board with a modern surfboard. While the studies on surfboards are limited, studies on planing surfaces are present in the literature and CFD proved to a useful tool to study the physics of the phenomenon. The acceleration is usually obtained in two steps: in the first step the surfer paddles, accelerating in order to catch the wave while in the second step he uses the wave behaviour by pitching the board to sharply increase the speed, reaching planing conditions. In the surfboard case, in order to generate the necessary amount of lift to support the surfboard plus the surfer, surfboards need to reach a certain speed. In such vehicles, the hydrodynamic lift is typically used to generate the majority of the vertical displacement and to support the vessel weight. On the other hand, the tail shape did not affect the performances of the board in the analyzed cases.įrom an engineering perspective, the surfboard can be considered as a three dimensional planing surface, similar to planing boats, vessels, and surface effect ship (SES) (Doctors, 2009). In particular, the static simulations showed that the rocker affects the performances by increasing the lift but also the drag of the board, also generating higher forces in maneuvering conditions. CFD proved to be a valid tool to compare the performances of the different shapes, bringing into light subtle but important differences between the designs. In the simulations, an Unsteady Reynolds Navier Stokes (URANS) approach is used, with the volume of fluid (VOF) method as free surface discretization method and the k-omega-SST turbulence model as numerical closure of the RANS equations. The commercial CFD code STAR-CCM+ is used in the present work to compare the performance of three different surfboards, with different curvature at the bottom and different tail shapes. This opens up a new design methodology, where the performances of the different shapes can be studied and quantitatively evaluated, highlighting details that would be otherwise impossible to identify from a field test. As a consequence, three dimensional (3D) computer models of the boards start to be available, and can be imported in Computational Fluid Dynamics (CFD) programs. In fact, surfboard manufacturing routines are moving towards more controlled and reproducible manufacturing processes, in particular Computer numerically controlled (CNC) shaping techniques. The present paper aims to show the potential of Computational Fluid Dynamics (CFD) solvers for surfboard design and its applicability by comparing three different surfboards with minimal changes in design. ![]()
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