init noise and inflow noise

[Madhurjya814]

Hi, I wanted to know what value of init and inflow noise is to be used for a pipe flow with periodic boundary condition for Re=10000?

[slaizet]

Hi,
Probably around 10% of the centreline velocity (=1) so around 0.1.
Best,
Sylvain

[Madhurjya814]

Hi, I had one more question. I wanted to know what is the boundary condition for scalar (phi1=zero at the inner wall ibm surface) in the original code for pipe flow simulation. Is it constant wall temperature or constant wall heat flux?
Thanks...

[slaizet]

constant wall temperature

[Madhurjya814]

Hi, I need some guidance regarding implementing isoflux boundary condition in pipe flow case with ibm=2. Where exactly in the code should be modified for isoflux condition? What are the important subroutines for modifying to isoflux condition? Do I need to change the pre correction pipe subroutines also? (I am asking for periodic boundary condition and non dimensional temperature).
Thanks...

[Madhurjya814]

Hi, Obtaining a turbulent state for a wall bounded flow is quite tricky. One option would be to obtain a turbulent state without a scalar and then restart the simulation with a scalar. Another option would be to obtain a turbulent state at a marginal resolution or using rotation like for the channel flow case (you make the pipe rotate to trigger turbulence, this is just a simple forcing term in the Navier-Stokes equation, see channel flow set up). Best, Sylvain

Restarting with scalar on later is not working after getting a turbulent flow....In the first iteration after restarting, scalar becomes infinity and it is diverging

[mathrack]

Hi, Obtaining a turbulent state for a wall bounded flow is quite tricky. One option would be to obtain a turbulent state without a scalar and then restart the simulation with a scalar. Another option would be to obtain a turbulent state at a marginal resolution or using rotation like for the channel flow case (you make the pipe rotate to trigger turbulence, this is just a simple forcing term in the Navier-Stokes equation, see channel flow set up). Best, Sylvain

Restarting with scalar on later is not working after getting a turbulent flow....In the first iteration after restarting, scalar becomes infinity and it is diverging

Please open a dedicated issue. I will lock the present discussion.