transient simulation

Andy Chen · September 2, 2009, 03:12

Dear experts:

I simulated free surface in transient model. It have to use mesh

adaption to solve free surface in steady model. Now, I have to simulate

free surface in transient model. But it can't use mesh adaption in

transient model. If it can't use mesh adaption taht causes the free

surface to be very rough. Does it have another solution method?

I have tried to let grid much finer. But it couldn't solve.

ghorrocks · September 2, 2009, 05:49

CFX does not support mesh adaption suitable for transient free surface work. The dynamic mesh adaption in Fluent does not work very well either but it is much better. I have had to develop my own free surface dynamic meshing in Fluent to get it to work properly.

Andy Chen · September 2, 2009, 23:16

Dear Ghorrocks:

So....you mean if I want to use mesh adaption for trasient model. I have had to

develop free surface dynamic meshing. Do you have any relate to free surface

dynamic meshing reference that could let me study.

And I have anothor question. Before I use flow-3d package that can solve free

surface problem very well for trasient model. Morever flow-3d doesn't need to carry

any hypothesis for mesh adaption function. Do you know how did flow-3d solve free

surface problem for trasient model. Thanks!!

ghorrocks · September 2, 2009, 23:56

My work on dynamic meshing for free surface modelling is proprietry so I can't share it - sorry. It is on Fluent anyway so it is probably not too useful for you.

All of these softwares can do free surface modelling. Your question was about dynamic mesh adaptation in free surface modelling - None of these softwares (CFX, Fluent or Flow3D) have a dynamic mesh capability for free surface modelling which works well. Flow3D has a different approach to VOF than CFX or Fluent in that it can model with a single fluid approach. While this makes it easier to model many free surface simulations it does have some inherent assumptions that the lighter phase does not affect the heavier phase.

Andy Chen · September 3, 2009, 01:44

Dear Ghorrocks:
Very thanks your precious responce. ^_^

Andy Chen · September 3, 2009, 03:55

Dear Ghorrocks:

How much did you spend time to write your dynamic mesh program? Is it program

difficult? Because my case is 3-D problem Whether the program was more difficulty.

ghorrocks · September 3, 2009, 06:10

Many weeks of work. It is not easy.

September 2, 2009, 03:12	transient simulation	#1
Andy Chen Member Yi-Lang Chen Join Date: May 2009 Posts: 58 Rep Power: 16	Dear experts: I simulated free surface in transient model. It have to use mesh adaption to solve free surface in steady model. Now, I have to simulate free surface in transient model. But it can't use mesh adaption in transient model. If it can't use mesh adaption taht causes the free surface to be very rough. Does it have another solution method? I have tried to let grid much finer. But it couldn't solve.

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September 2, 2009, 05:49		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,697 Rep Power: 143	CFX does not support mesh adaption suitable for transient free surface work. The dynamic mesh adaption in Fluent does not work very well either but it is much better. I have had to develop my own free surface dynamic meshing in Fluent to get it to work properly.

September 2, 2009, 23:16		#3
Andy Chen Member Yi-Lang Chen Join Date: May 2009 Posts: 58 Rep Power: 16	Dear Ghorrocks: So....you mean if I want to use mesh adaption for trasient model. I have had to develop free surface dynamic meshing. Do you have any relate to free surface dynamic meshing reference that could let me study. And I have anothor question. Before I use flow-3d package that can solve free surface problem very well for trasient model. Morever flow-3d doesn't need to carry any hypothesis for mesh adaption function. Do you know how did flow-3d solve free surface problem for trasient model. Thanks!!

September 2, 2009, 23:56		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,697 Rep Power: 143	My work on dynamic meshing for free surface modelling is proprietry so I can't share it - sorry. It is on Fluent anyway so it is probably not too useful for you. All of these softwares can do free surface modelling. Your question was about dynamic mesh adaptation in free surface modelling - None of these softwares (CFX, Fluent or Flow3D) have a dynamic mesh capability for free surface modelling which works well. Flow3D has a different approach to VOF than CFX or Fluent in that it can model with a single fluid approach. While this makes it easier to model many free surface simulations it does have some inherent assumptions that the lighter phase does not affect the heavier phase.

September 3, 2009, 01:44		#5
Andy Chen Member Yi-Lang Chen Join Date: May 2009 Posts: 58 Rep Power: 16	Dear Ghorrocks: Very thanks your precious responce. ^_^

September 3, 2009, 03:55		#6
Andy Chen Member Yi-Lang Chen Join Date: May 2009 Posts: 58 Rep Power: 16	Dear Ghorrocks: How much did you spend time to write your dynamic mesh program? Is it program difficult? Because my case is 3-D problem Whether the program was more difficulty.

September 3, 2009, 06:10		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,697 Rep Power: 143	Many weeks of work. It is not easy.