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Lilly May 24, 2012 10:20

periodic boundary condition-profile
Dear all,

we want to simulate a periodic boundary condition using FLUENT for a straight tube. Inlet and outlet of the tube should be "connected" via this periodic boundary condition and we finally managed to reach this connection.
Our problem is that we wanted to use a sinusoidal pressure variation (pressure variation in time) at the "connected" boundaries. Therefore we created a profile-file, but we cannot set it with the periodic boundary condition (we can just set flow direction, pressure gradient and mass flow there). Is there any way to set our profile as periodic bc?
Thanks a million for all your help and ideas!

sbaffini May 24, 2012 17:49

If your grid has identical cells distributions on both inlet and outlet then the periodic condition can be set in fluent by grid/modify/make-periodic, as you probably already figured out.

However, i don't understand why your sinusoidal pressure variation is not compatible with periodic b.c.s (say, fixing the pressure gradient). If the problem is the time variation you can simply put the pressure gradient equal to 0 in the relative periodic boundary condition panel and then add an x-source term via UDF which is the exact replica of the pressure gradient (in UDFs you can add the time-variation).

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