Second derivative

March 27, 2005, 14:16

Hi cfx users,

Still don't manage to calculate d2u/dx2, which is equal to Velocity u.Gradient x.Gradient x Someone to help me?? Thanks,

Thomas

March 28, 2005, 13:02

can you explain you problem more detailed? calculate d2u/dx2 in the CFX-UDF? or in other place?

March 28, 2005, 14:38

Hey. I would like to calculate it with a Fortran routine and the command user_getvar. With that I'm able to obtain the gradient: so just velocity u.gradient.gradient (and not velocity u.gradient x.gradient x!!)... as I cannot use the variable created in cfx-post: velocity u.gradient x. Do you have any suggestion to calculate d2u/dx2?? It doesn't matter how. Thanks

March 27, 2005, 14:16	Second derivative	#1
Thomas Guest Posts: n/a	Hi cfx users, Still don't manage to calculate d2u/dx2, which is equal to Velocity u.Gradient x.Gradient x Someone to help me?? Thanks, Thomas

March 28, 2005, 13:02	Re: Second derivative	#2
liumalin Guest Posts: n/a	can you explain you problem more detailed? calculate d2u/dx2 in the CFX-UDF? or in other place?

March 28, 2005, 14:38	Re: Second derivative	#3
Thomas Guest Posts: n/a	Hey. I would like to calculate it with a Fortran routine and the command user_getvar. With that I'm able to obtain the gradient: so just velocity u.gradient.gradient (and not velocity u.gradient x.gradient x!!)... as I cannot use the variable created in cfx-post: velocity u.gradient x. Do you have any suggestion to calculate d2u/dx2?? It doesn't matter how. Thanks

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