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 Lilly February 18, 2013 10:41

periodic flow-solve flow equation

Dear all,

I want to simulate a species transport inside periodic pulsatile flow. A friend of mine is using Open Foam and he told me, that he can calculate the flow once and use this solution later. During the rest of the simulation Open Foam is just calculating the species transport, which saves a lot of calculating time.
I found that you can choose which equations to solve at Fluent as well (Solution Methods->Equations). But how can I choose to consider a periodic pulsatile solution for the flow (and not a constant flow)?

Thanks a million for any help and idea!
Lilly

 Lilly February 28, 2013 04:37

Does anybody have an idea how to solve this?

 diamondx February 28, 2013 14:40

by periodic you mean profile at the inlet change along a direction ?

 Lilly March 1, 2013 04:15

Thank you, Ali!
I mean the velocity is spatially constant at the inlet-face, but it changes with time. After about one second the cycle starts again from the beginning. It's the blood velocity profile inside a coronary vessel which I want to simulate (transient).
Thank you for any help and idea!
Lilly

 diamondx March 1, 2013 09:50

for a "transient velocity profile", you will have to use UDF. i guess you are familiar with that ? for an unsteady velocity profile , use this code:

Quote:
 /************************************************** ********************/ /* unsteady.c */ /* UDF for specifying a transient velocity profile boundary condition */ /************************************************** ********************/ #include "udf.h" DEFINE_PROFILE(unsteady_velocity, thread, position) { face_t f; begin_f_loop(f, thread) { real t = RP_Get_Real("flow-time"); F_PROFILE(f, thread, position) = 20. + 5.0*sin(10.*t); } end_f_loop(f, thread) }
What you have to do: replace the "20. + 5.0*sin(10.*t)" by your own equation... i hope it will help

 Lilly March 4, 2013 08:10