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adapt viscous resistance based on velocity / UDF

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Old   April 17, 2009, 11:30
Default adapt viscous resistance based on velocity / UDF
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I am new here, so hi everyone!

I am currently simulating the
(laminar) flow through a filter medium / porous zone. After an initial
state (viscous resistance of filter is homogeneous) I want to adapt
(increase) the viscous resistance of the filter based on the magnitude
of the velocity (~ flow) in each cell of the porous zone. This will
lead to a new solution of the problem. Now the viscous resistance can
be again adjusted etc.

Now I have some questions related to my work:

a)
Can I access (meaning read/write) the viscous resistance of a cell
somehow OUTSIDE of the DEFINE_PROFILE macro hooked to the viscous
resistance of the porous zone?

b) If I use the unsteady state
solver, I can set the iteration intervals at which the UDFs shall be
updated. Is there any way to tell FLUENT only to update the UDFs every
time step (regardless of the iterations)?

c) In general: How
could I approach the "stepwise" nature of the problem best? Meaning:
calculate a solution -> adjust the boundary conditions in this case
viscous resistance) using the solution -> calculate the new solution
-> adjust again etc.

Any help will be greatly appreciated!
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Old   April 20, 2009, 07:12
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a) Still not sure if / how that works

b) One can use the variable first_iteration, which is true only at the first iteration of every time step

But I have another question: How can I display the cell values of the viscous resistance? I not only want to look at the velocities inside my porous zone, but also at the viscous resistances of the cells.
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Old   April 20, 2009, 10:08
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Ok, just write it to UDM and FLUENT will be able to display it. Question remaining: a).
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