x-momentum urf and sliding mesh

kike · July 28, 2011, 15:04

Hello,

I am trying to model a box that travels through a conveyor as as fluids flow inside from the top. Unsure of which method might be the best for this case I decided to give it a try with sliding mesh. What I did was split the conveyor in two parts and make the bottom part, that had the outline of box, the zone that would move. Initially I wanted to move the box only but I think this is only achieved with a dynamic mesh, thus I move the whole bottom part. I also failed to include a solid zone for the box and its only its exterior geometry what is taken into account (however I think if I want to consider heat transfer to the box I would have to fix this issue).

Anyways, that is my setup, unfortunately, I was having a lot of converging issues and I decided to simplify the model to an inviscid, no energy flow. This way I didnt have to worry about the wall motion which is still a little bit obscure to me. However, even like that, the simulation was not converging, I kept getting the same x-momentum divergence message all the time until it finally did converge when I changed my momentum under relaxation term to 0.01. This is too low for me and I don't know if I should really trust the result, the motion of the mesh is right but when I look at the animations of the pathlines they seem to be incomplete or not make sense..

I would really appreciate anyone's opinion on this case or ideas. Before hand, thanks for taking your time to read this thread.

kike · August 1, 2011, 18:07

Unfortunately, I am starting to think that Dynamic Mesh is the way to go for this one since for some reason my fluid doesnt seem to be willing to cross from one zone to the other.

July 28, 2011, 15:04	x-momentum urf and sliding mesh	#1
kike New Member Join Date: Jul 2011 Location: Boston, MA Posts: 15 Rep Power: 15	Hello, I am trying to model a box that travels through a conveyor as as fluids flow inside from the top. Unsure of which method might be the best for this case I decided to give it a try with sliding mesh. What I did was split the conveyor in two parts and make the bottom part, that had the outline of box, the zone that would move. Initially I wanted to move the box only but I think this is only achieved with a dynamic mesh, thus I move the whole bottom part. I also failed to include a solid zone for the box and its only its exterior geometry what is taken into account (however I think if I want to consider heat transfer to the box I would have to fix this issue). Anyways, that is my setup, unfortunately, I was having a lot of converging issues and I decided to simplify the model to an inviscid, no energy flow. This way I didnt have to worry about the wall motion which is still a little bit obscure to me. However, even like that, the simulation was not converging, I kept getting the same x-momentum divergence message all the time until it finally did converge when I changed my momentum under relaxation term to 0.01. This is too low for me and I don't know if I should really trust the result, the motion of the mesh is right but when I look at the animations of the pathlines they seem to be incomplete or not make sense.. I would really appreciate anyone's opinion on this case or ideas. Before hand, thanks for taking your time to read this thread.

August 1, 2011, 18:07		#2
kike New Member Join Date: Jul 2011 Location: Boston, MA Posts: 15 Rep Power: 15	Unfortunately, I am starting to think that Dynamic Mesh is the way to go for this one since for some reason my fluid doesnt seem to be willing to cross from one zone to the other.