Why is e-20 m ^ 2 the lowest permeability value that ansys cfx allows?

sasterror · September 21, 2020, 23:26

best regard,

1. Why is e-20 m ^ 2 the lowest permeability value that ansys cfx allows?

2. I found in a forum that someone had been able to work with lower values using UDF, how could that be done?

3. Is there any reference that you recommend to me regarding question 1.?

thanks.

ghorrocks · September 22, 2020, 06:14

1. Some parameters have divide by zero problems in Navier Stokes equations, so some parameters cannot be exactly zero.

2. UDF is Fluent. So it was probably Fluent.

3. There is no reference other than the CFX documentation, and I am sure it does not discuss this. You can ask ANSYS support if you really need to know I guess.

September 21, 2020, 23:26	Why is e-20 m ^ 2 the lowest permeability value that ansys cfx allows?	#1
sasterror New Member Sebastián A. Join Date: Oct 2017 Posts: 11 Rep Power: 8	best regard, 1. Why is e-20 m ^ 2 the lowest permeability value that ansys cfx allows? 2. I found in a forum that someone had been able to work with lower values using UDF, how could that be done? 3. Is there any reference that you recommend to me regarding question 1.? thanks.

September 22, 2020, 06:14		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,816 Rep Power: 144	1. Some parameters have divide by zero problems in Navier Stokes equations, so some parameters cannot be exactly zero. 2. UDF is Fluent. So it was probably Fluent. 3. There is no reference other than the CFX documentation, and I am sure it does not discuss this. You can ask ANSYS support if you really need to know I guess. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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