how to run explicit time scheme in CFX

lostking18 · April 6, 2018, 11:30

Hi, there, I know for the steady state simulation, the pseudo time marching is obtained by 1st order implicit Euler method. Is there any method, such as expert parameter that we can use to implement the 1st order explicit Euler method? I have specific need for this temporal scheme despite its instability. Or if we use transient simulations, is there any chance we can run the explicit simulations?

ghorrocks · April 7, 2018, 06:01

No, you cannot change the time marching scheme for a steady state flow.

Can you run an explicit transient simulation in CFX? No.

CFX does not give you much control of the choice of numerical scheme. If you want to compare different numerical schemes you better go to software like Fluent or StarCD, or even better write it yourself.

lostking18 · April 7, 2018, 14:59

Quote:

Originally Posted by ghorrocks

No, you cannot change the time marching scheme for a steady state flow.

Can you run an explicit transient simulation in CFX? No.

CFX does not give you much control of the choice of numerical scheme. If you want to compare different numerical schemes you better go to software like Fluent or StarCD, or even better write it yourself.

Hi, Glenn, thank again! It's so sad that CFX looses the flexibility of this part. I may have to turn my head to Fluent.... But clearly the commercial code all have such kind of resitrictions here and there. I guess write the solver from zero is almost impossible for me. In terms of the open source code, do you have any recommendations? Openfoam? SU2?

ghorrocks · April 8, 2018, 05:58

All those open source codes are useful. There are plenty of simple open source codes which show the various solver methods, so if you don't want to write one yourself you can have a look at an open source one instead.

April 6, 2018, 11:30	how to run explicit time scheme in CFX	#1
lostking18 Member phd Join Date: Oct 2013 Posts: 76 Rep Power: 12	Hi, there, I know for the steady state simulation, the pseudo time marching is obtained by 1st order implicit Euler method. Is there any method, such as expert parameter that we can use to implement the 1st order explicit Euler method? I have specific need for this temporal scheme despite its instability. Or if we use transient simulations, is there any chance we can run the explicit simulations?

April 7, 2018, 06:01		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	No, you cannot change the time marching scheme for a steady state flow. Can you run an explicit transient simulation in CFX? No. CFX does not give you much control of the choice of numerical scheme. If you want to compare different numerical schemes you better go to software like Fluent or StarCD, or even better write it yourself. lostking18 likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

April 8, 2018, 05:58		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	All those open source codes are useful. There are plenty of simple open source codes which show the various solver methods, so if you don't want to write one yourself you can have a look at an open source one instead. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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