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-   -   ship motion simulation (https://www.cfd-online.com/Forums/cfx/153236-ship-motion-simulation.html)

esmail May 21, 2015 03:59

ship motion simulation
 
hi
i want simulation ship motion in calm water with 5 m/s speed.
but i donot know how i can do this.
please help me.
thanks

Thomas MADELEINE May 21, 2015 04:37

I can't believe there is no tutorial about it. It is the basic for this domain, have you search for one ?
https://www.youtube.com/watch?v=M4IpdWVNBZI

I don't know this domain but I would create a big domain half full of water with velocity (the other half with air and velocity too).
Then create a rigid body with MFX and block the translation of the ship (only Z authorized).

It is always easier to move the fluid than the body.

esmail May 21, 2015 04:50

hi dear
thanks for your promptly Cooperation
i want to know , i can use 3d rigid body?
how i can use mfx ?

Thomas MADELEINE May 21, 2015 05:18

I have never tried something like that before, so my first advice will be to listen to people who know ^^

MFX (Multifield coupling) in the analysis type panel. But I was wrong you don't need it (well I am not sure).

can you have a look on the webinar of the 9th december 2014 about 2-Way FSI ? there is an example of this with rigid body FSI (so no coupling in this).
This is not a tutorial but you can ask to the support the definition file.

esmail May 21, 2015 05:45

do you know about sliding mesh?
i want to know ,how can used it?

Thomas MADELEINE May 21, 2015 05:55

sliding mesh is an interface where the mesh is sliding. The mesh is fixed in both domain but the two domain are sliding. The most common examples are turbomachinery between rotor and stator.

I don't think it is useful here because the large displacement you will have will be unpredictable. Sliding mesh is use when the movement is simple aka rotation or translation.

esmail May 21, 2015 06:02

if our model change to small model (1 meter) and motion restrict to heave motion , you think we can use it?

Thomas MADELEINE May 21, 2015 07:02

what do you want to see exactly ?

the sliding mesh can be use with a sphere around the ship to allow any rotation. But I am not sure that it will be efficient

esmail May 21, 2015 07:06

how i can apply the sliding mesh?
i should define sub domain and cut my model or not?

Thomas MADELEINE May 21, 2015 07:28

sliding mesh is at an interface so you have to cut your domain in two parts.
Then you can mesh it separately (it is not an obligation).
at the end you allow the domain with the ship to slide on the other domain.

here an example of people who have used sliding mesh (I hope):
Problem in Mesh Displacement at middle of Pool


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