Grasshopper

algorithmic modeling for Rhino

# Hydrostatics in grasshopper

As a new grasshopper user, I am trying to solve hydrostatic caculations...

I did some try with hoopsnake, and now with Anemone... I can reach the static equilibrium with the correct displacement, but when I try to work with two loops and change the trim angle AND the displacement, it doesnt work properly...

Does anyone has an idea?

The gh programm is here: StabTest.gh

Sorry if it is not done properly, I ve been using GH for a week only...

Simon

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### Replies to This Discussion

Very interesting post!! I made once an script on VBA for Rhino to calculate the hydrostatics... but I never have tried to calculate them on GH!!

Here's what I think you should do :

1 create a loop that aligns the center of gravity with the center of buoyancy. E parameter of this anemone would be (xCG - xCB)² < thrsld²

2 create a  loop that sets the displacement at the desired value. You've done that but I would recommend moving the object rather than the water.

now once you've done that, go back to the anemone tutorial and nest one in another.

In that post in the hoopsnake group I talked about how to guess the amount of rotation from the usual longitudinal stability analysis (metacenter theory). It helps a HUGE deal with convergence so I really advise you to go there.

Also, don't discourage yourself. with 7 days of gh it is not a trivial undertaking.

Which post in Hoopsnake you re talking about?

Simon,

I checked your file, seems you took the long way! I didn't even understand why 3 loops?

Check out this file, seems to work ok here.

Attachments:

Yep, I was trying to understand Anemone.

Actually I did different (see file attached) using ONE Anemone loop with two parameters (D0 and D1)

I am trying to improve convergence now. But for my kind of hull, I can get converged solution after 30 loops... Quite fast...

If someone is interested on working on the convergence?

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