Sloshing - Free surface

hossein_sml · January 3, 2016, 02:55

Hi,

I am trying to simulate sloshing in rotating cube (±30 degrees) (2D).
The cube is rotating around center of lower side.

mesh :structured
Homogeneous Model
Turbulence : None (Laminar)

Unfortunately when cube rotates, the free surface gets irrational slope, and seems that water does not transfer properly between parts ( left and right of wall) \
\
\
\
What is the problem?
How can I fix it?

I have tried other turbulence models, but it was not the solution and nothing changed. Even I turned on surface tension, but nothing changed.

Please help me ASAP.

ghorrocks · January 4, 2016, 06:10

Please attach your CEL.

Are you modelling the rotation using rotating frames of reference or moving mesh?

hossein_sml · January 4, 2016, 07:25

the mesh is moving ( Boundary and mesh is moving )

hossein_sml · January 4, 2016, 07:26

Please click one of the Quick Reply icons in the posts above to activate Quick Reply.

ghorrocks · January 4, 2016, 07:37

This could be caused by:

* Inadequate convergence
* A mesh error where the left and right side of the meshes are not connected
* The left to right flow is slow, so you have to run it for more simulation time for the flow to reach the equilibrium level.

hossein_sml · January 4, 2016, 08:03

- All meshes and boundary are moving with same rotational speed.
- Max. Coeff. Loops : 10
Residual Target :1e-05

- What do you mean from "The left to right flow is slow, so you have to run it for more simulation time for the flow to reach the equilibrium level"
in one simulation, the simulation continued for 4-5 s, but results got worst.

ghorrocks · January 4, 2016, 18:33

You need to do a sensitivity analysis to see if your convergence is tight enough. Run a tighter or looser residual and see if it makes any difference.

You will need to show more details of what you are doing if you want us to help you more. Please attach an image of your mesh and CCL.

hossein_sml · January 5, 2016, 03:52

I tried various residuals but nothing changed.

I have used structural mesh as below, Also I tried with unstructured (Hexa) mesh, but it did not work too.

about ccl which part do you need to know?

ghorrocks · January 5, 2016, 19:45

All of the CCL. It is a small text file so should be easy to attach to the forum post.

January 3, 2016, 02:55	Sloshing - Free surface	#1
hossein_sml New Member hossein Join Date: May 2012 Posts: 28 Rep Power: 14	Hi, I am trying to simulate sloshing in rotating cube (±30 degrees) (2D). The cube is rotating around center of lower side. mesh :structured Homogeneous Model Turbulence : None (Laminar) Unfortunately when cube rotates, the free surface gets irrational slope, and seems that water does not transfer properly between parts ( left and right of wall) \ \ \ \ What is the problem? How can I fix it? I have tried other turbulence models, but it was not the solution and nothing changed. Even I turned on surface tension, but nothing changed. Please help me ASAP. Last edited by hossein_sml; January 14, 2016 at 03:04.

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January 4, 2016, 06:10		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Please attach your CEL. Are you modelling the rotation using rotating frames of reference or moving mesh?

January 4, 2016, 07:25		#3
hossein_sml New Member hossein Join Date: May 2012 Posts: 28 Rep Power: 14	the mesh is moving ( Boundary and mesh is moving )

January 4, 2016, 07:26		#4
hossein_sml New Member hossein Join Date: May 2012 Posts: 28 Rep Power: 14	Please click one of the Quick Reply icons in the posts above to activate Quick Reply.

January 4, 2016, 07:37		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	This could be caused by: * Inadequate convergence * A mesh error where the left and right side of the meshes are not connected * The left to right flow is slow, so you have to run it for more simulation time for the flow to reach the equilibrium level.

January 4, 2016, 08:03		#6
hossein_sml New Member hossein Join Date: May 2012 Posts: 28 Rep Power: 14	- All meshes and boundary are moving with same rotational speed. - Max. Coeff. Loops : 10 Residual Target :1e-05 - What do you mean from "The left to right flow is slow, so you have to run it for more simulation time for the flow to reach the equilibrium level" in one simulation, the simulation continued for 4-5 s, but results got worst.

January 4, 2016, 18:33		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	You need to do a sensitivity analysis to see if your convergence is tight enough. Run a tighter or looser residual and see if it makes any difference. You will need to show more details of what you are doing if you want us to help you more. Please attach an image of your mesh and CCL.

January 5, 2016, 03:52		#8
hossein_sml New Member hossein Join Date: May 2012 Posts: 28 Rep Power: 14	I tried various residuals but nothing changed. I have used structural mesh as below, Also I tried with unstructured (Hexa) mesh, but it did not work too. about ccl which part do you need to know?

January 5, 2016, 19:45		#9
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	All of the CCL. It is a small text file so should be easy to attach to the forum post.