CFD sail profile help

[daverave]

Hello everyone,

I'm new to this forum so please move this thread if it is in the wrong spot.

For my final years dissertation i chose to do some computational fluid modelling of the aerodynamics of sails. I'm blowing non-tubulent wind through laser sails at different points of sailing.

I am a laser sailor, race regularly but not excessively and finish usually in the 2/3 of the fleet at club racing, so I know how things work reasonably well.

• To create the 2d sail geometry I use a program called Gambit.

• To run the CFD I use Fluent

• In order to create the sail curve I use this online Java applet: http://www.ppart.de/aerodynamics/profiles/NACA4.html. The Java applet can create aerofoil profiles depending on thickness (set it to zero), skew, camber etc (as you can see on the site). I want to model a laser sail through close hauled, beam reach and broad reach points of sailing. For close hauled I know we need cunningham on, outhaul tight, kicker/vang tight to depower - the sail needs to act as a foil to prevent stalling. Vice versa for downwind.

For each point I think I have the correct sail shape in plan view.

Here's my attempt:

Close Hauled

Maximum camber (0-9):3
Max camber pos. (0-9): 2
Thickness (0-99): 0
Point size: 4

Beam Reach


Broad Reach


Am I correct? Using the link, what do you think the three points should be set at? Use the sliders to change the aerofoil's shape - make thickness zero (negligable) and ignore the sliders below "# Points".

[Humberto]

If you just sail a Laser, why don't you put a trimming line on the, let's say, 1/3 of the sail and take a picture of it, from bottom-up? Then you can easily compare the curve with the shape you are selecting in the software ... this is usually done in larger yachts. You can see an exmple with a Finn with ShapePlot, or you can try AccuMeasure. To cite a few examples.

Good look!