# User viscosity routine and user scalars?

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 July 21, 2002, 18:00 User viscosity routine and user scalars? #1 Jeff Guest   Posts: n/a Hi All I asked this question in the general forum and someone pointed me to star-cd. As it turns out, I am pretty sure we have star at work so I would like to ask the same question here to confirm that I can do what I need to do. I need to be able to model a non-Newtonian fluid and it will require a user subroutine. The problem would require standard arguments to the viscosity function like Temperature, strain-rate, etc.. but would also require the gradient of a user scalar variable, which is the solution to a Poisson equation. It would look something like this: mu=mu(T, s-dot, |grad(c)|) Can Star-CD handle this situation? Hopefully, I will get a hold of some manuals next week. Is there a specific section for me to look at? Thanks Jeff

 July 22, 2002, 04:43 Re: User viscosity routine and user scalars? #2 Richard Guest   Posts: n/a STAR can handle this situation. The subroutine you need to use is VISMOL, but you'd need to contact your local CD-adapco support office to get help on incorporating scalar gradients into the subroutine. It's easy to do, but not without some help from a support engineer.

 July 22, 2002, 07:28 Thanks, I'll give them a call.(nm) #3 Jeff Guest   Posts: n/a Thanks

 January 6, 2003, 05:26 Re: User viscosity routine and user scalars? #4 Alexander Guest   Posts: n/a Hi Jeff! I have to solve the similar ploblem. The coefficient in the motion equation is governed by Poisson equation. After solving Poisson equation it is necessary to calculate the gradient of the scalar. What STAR technique would you suggest to use: a) to solve Poisson equation; b) to calculate the gradient (vector) of the scalar. Thanks Alexander