I found this paper the other day on the newly launched Reef Journal website:
“Optimization of Surfboard Fin Design for Minimum Drag by Computational Fluid Dynamics”
Basically: Do glass-on fins induce less or more drag than boxed fins?
and here is a little abstract:
“This paper describes work being done at Swansea University on the design of wave riding surfboards, with preliminary emphasis on the stabilising fins. Two specific CAD (Computer Aided Design) tools are being developed, one for surfboard design and the other for fin design, both of which allow export of NURB (Non Uniform, Rational, B-spline) surface geometry in the IGES (Initial Graphics Exchange Specification) format. The fin design tool has the capability of allowing different National Advisory Committee for Aeronautics (NACA) foils series to be set at separate cross-sections along the fin.
Fins and surfboard/fin combinations can be imported directly into the CFD (Computational Fluid Dynamics) package FLUENT and with careful consideration of surfing dynamics to obtain values of critical flow variables, estimates have been obtained of the pressure and friction drag forces, which are thought to correspond to those occurring in practice and will be validated experimentally at a later stage. These results, however, have already been used to examine a number of disputes in the manufacturing industry, one of which is whether glasson fins induce more or less drag than equivalent fins fixed to the board by a box. This component of the research is just a small part of the larger objective which is to bring scientific and engineering advances into the design and manufacture of surfboards. As the project progresses, CFD will be used to resolve more complex drag components, such as wave drag (free surfaces), induced (vortex) drag and cavitational drag, as well as being coupled to a finite element stress analysis to optimize flexural properties of boards and fins.”
Fo those who are not scared of physics/modelling sciences and wanna check it out, here is the link: http://thereefjournal.com/files/7._Lavery_Foster_and_Carswell.pdf
For the others, who just wanna get the answer, well...
Just skip everything and go straight to the conclusion...
The answer is pretty interesting!
