[jiemodanni]

hi,
Now I am faced with this problem. I want to calculate the fully developed flow field in the circular pipe. In order to save resources, I use the flow periodic boundary condition.Because I cannot get the pulse of speed, my time step size has been set. I doubt that the periodic boundary can be used for transient calculation. I hope you can help me and tell me how to set it.Fluent is version 16.0.
thank you.

[LuckyTran]

Periodic BC's can be used in transient calculation. Your doubts are completely unfounded.

[jiemodanni]

Originally Posted by LuckyTran

Periodic BC's can be used in transient calculation. Your doubts are completely unfounded.

I first calculated the steady-state calculation example, and then took the steady-state result as the initial condition to calculate the unsteady flow field, but I did not observe the pulsating phase of the velocity, I gave a fixed mass flow rate.10,000 steps have been calculated, and the time step length is 0.0001. Can you tell me specifically how to set it? I don't know if there is something wrong with my setting.
thank you

[LuckyTran]

Fully developed pipe flow doesn't develop pulsatile behavior... why are you looking for it?

[jiemodanni]

Originally Posted by LuckyTran

Fully developed pipe flow doesn't develop pulsatile behavior... why are you looking for it?

I want to get this information about the instantaneous flow field. I've attached the picture below. I'm just going to use the transient calculation and the periodic boundary. I don't know why I can't get it。velocity.png

[jiemodanni]

Originally Posted by LuckyTran

Fully developed pipe flow doesn't develop pulsatile behavior... why are you looking for it?

But all I get is this kind of flow field distribution, whether it's steady state or transient.
velocity1.jpg

The following is the periodic boundary condition that I set.
setting.jpg

Good man, can you tell me what I can do to get the transient velocity field? Thank you.

[LuckyTran]

you need to be running transient LES