Random Boundary Condition

RichardM · June 21, 2013, 04:38

Hi CFX-Users,

I'm trying to use a random boundary condition for a wall - e.g. thermal fluctuation. I want to insert a mean surface temperatur with a statistical variation within a defined range of values for every single volume element at the wall. I only need a random number in the range of [0;1]. But I can not find any function in CFX-Pre to do this. Normally I use the Expressions.
Do I have to program it in Fortran?

Thanks for your help.
Richard

ghorrocks · June 21, 2013, 07:59

There is no CEL expression I know of for random numbers. You could either generate a chain of random numbers and get them into CFX as an interpolation function, of you could use a fortran user subroutine.

June 21, 2013, 04:38	Random Boundary Condition	#1
RichardM New Member Richard Join Date: Apr 2012 Posts: 1 Rep Power: 0	Hi CFX-Users, I'm trying to use a random boundary condition for a wall - e.g. thermal fluctuation. I want to insert a mean surface temperatur with a statistical variation within a defined range of values for every single volume element at the wall. I only need a random number in the range of [0;1]. But I can not find any function in CFX-Pre to do this. Normally I use the Expressions. Do I have to program it in Fortran? Thanks for your help. Richard

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June 21, 2013, 07:59		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	There is no CEL expression I know of for random numbers. You could either generate a chain of random numbers and get them into CFX as an interpolation function, of you could use a fortran user subroutine.