Sail Simulation#

Foreword#

As I sailed my boat I got curious about different shapes the sail takes depending on the direction and speed of wind. I asked ChatGPT to write me a study book about the physics. To make it more engaging, it add a mathematical model for interactive simulations. I didn’t want the complications of a moving boat, trimming, keeling, and all that.

So, imagine a mast fixed vertically in the ground with a sail attached to it. The wind blows horizontally on the sail, changing it’s shape, but nothing else moves. The shape changes because air and gravity exert forces on flexible cloth. Basically, it’s combination of elastic cloth and airflow simulation.

The sailing terms are not important here, but I like to plug them wherever possible:

  • The mast is the vertical support, fixed to the ground.

  • The boom is the horizontal support (for the sake of this study, it’s fixed in position as well).

  • The luff is the cloth edge attached to the mast.

  • The foot is its bottom edge attached to the boom.

  • The leech is the third side, away from the mast, remains free.

I read this “book”, and made a number of iterations to make it good. So it’s not an unhinged AI slop, I actually like it, learned a lot, and had fun.

Chapters#