Object floats in 2D but does not float in 3D
Hello, using the example from the main/floating "CaseFloatingVal2D" I removed the periodic boundaries option and put borders on the right, left, back and front. I did not change other parameters and I could see the cylinder sink.
Then I changed the 'y' range to do a 3D simulation and the cylinder floats. Even though it has a density of 1200 kg/m^3 and the fluid has a density of 1000 kg/m^3 it floats. Why?
I also tried with bigger relativeweight and used DesignSPhysics with different densities for the cylinder but got the same result: objects with bigger densities than the fluid float. Why is this happening? What am I not considering?
I attached the xml in 3D in case you want to review it.
I would appreciate any help
Comments
It is recommended that you assign mass to floating bodies instead of density as the mass calculation in the latter case depends on particle spacing as well.
Also, while I am not sure of your specific use case, the particle spacing of 0.4 is fairly large. Try reducing the value to see if that helps.
Thank you, I will use mass and return with the result.
For the particle spacing I used the bigger value possible in order to have a fast simulation because I'm using CPU. I will reduce it and see.
Thanks again for answering!
Only density is equivalent between a 2D and 3D case.
Not sure how you have converted the 2D case to an equivalent 3D one... not sure if you have done it properly.
Finally, the mass in 3D can be converted to the bidimensional mass using mass/widthY
Regards
The only thing I changed when converting from 2D to 3D was the y range. Density was left the same. But in 3D it floats.
Imagine a cylinder falling in a fluid with density x (the 3D case). What I've seen from several simulations is that the cylinder must have a density of 4x or higher for it to sink. I don't know why this is happening.
If you have only change the y range then you have to check the length of the 3-D cylinder and how it looks now the 3D case?
You should plot the case first to understand what you are simulating. what is the width of the cylinder now? do you have front and back walls? etc