Wow Great find - thats going to give me hours of fun. In terms of understanding layer separation and angle of attack. Am I correct in saying that the flow over the fin on the side thats providing lift(Working Side) is the most important and that water separation on the other side will induce some drag - you cannot avoid it. The amount of drag induced on the dead side need to be considerably less than the lift provided on the working side, thats the balance you should be working towards.
Wow Great find - thats going to give me hours of fun. In terms of understanding layer separation and angle of attack. Am I correct in saying that the flow over the fin on the side thats providing lift(Working Side) is the most important and that water separation on the other side will induce some drag - you cannot avoid it. The amount of drag induced on the dead side need to be considerably less than the lift provided on the working side, thats the balance you should be working towards.
Blakestah, Halcyon, Bert ?
Both sides of the fin are important sources of lift.
A real limitation of software like that is that fins are not infinitely long foils. Almost all foil theory comes from work that presumes “wing” aspect ratio is greater than 5. That means the wing length is 5 times longer than its distance in the flow direction (or chord length).
However, this doesn’t apply to ANY surfing fins. They are usually less than 2 in aspect ratio, and many approach aspect ratios of 1. They also are heavily raked and have a large perpendicular planar surface. As such, how you handle rake and tip-chord-length-reduction will have a very large impact that programs like that will not yield any insight into. In addition, the use of cutaways is well-established for center fins, but also outside the scope of that program.
In addition, most people have little idea of the range of angle of attacks in a surfing fin during common maneuvers like bottom turns or cutbacks.