[Dexonin]

Hey Guys,
I have looked in many forums / reddit / Tutorials, but couldnt find any solution to this. Maybe you guys can help me out

I just finished my simulation for a gas flow trough a Pipe. It looks like this:
https://gyazo.com/c9c343ef38749ab49ca2e2ff2aae064a

The only Initial Condition I have is the Inlet velocity. Now I want to change the value of this Condition, but dont want to run a whole new simulation.
Is there a way I can see like the pressure for different velocity initial conditions?

Thanks in advance

[fluid23]

Inlet velocity isn't an initial condition, its a boundary condition. Initial conditions are values assigned to every cell in the domain prior to calculation.

If you want to reuse previous results from your current solution as initial conditions in your next run, go to Solution > Clear Solution and unselect 'Fields' then click 'OK'. This will reset iteration to 1 but keep the values for the various fields functions stored in your domain. If you need to remesh go ahead. It will interpolate the values on to the new mesh after the mesher is finished. Adding or changing geometry can get a little tricky though.

[Dexonin]

Thanks for the answer.
Yea I have the Inlet Velocity as a Boundery Condition but also a set velocity as an Initial Condition. I just set the Inlet velocity as the same for my initial Condition.
I want to keep the same mesh and all, only change the initial velocity and therefore the boundery condition as well. Or is this not nessesary?
And how do I proceed then?

[ashokac7]

Originally Posted by Dexonin

Thanks for the answer.
Yea I have the Inlet Velocity as a Boundery Condition but also a set velocity as an Initial Condition. I just set the Inlet velocity as the same for my initial Condition.
I want to keep the same mesh and all, only change the initial velocity and therefore the boundery condition as well. Or is this not nessesary?
And how do I proceed then?

Initial condition don't affect the results a lot. They are there for early convergence. You can proceed with (0,0,0) initial condition for velocity.


And if you want to change the Boundary condition then you have to run the simulation once again. Otherwise you can put the different velocity BC values in tabular format or defined as field function and can run multiple cases at once.

[gikamc]

Originally Posted by ashokac7

Initial condition don't affect the results a lot. They are there for early convergence. You can proceed with (0,0,0) initial condition for velocity.


And if you want to change the Boundary condition then you have to run the simulation once again. Otherwise you can put the different velocity BC values in tabular format or defined as field function and can run multiple cases at once.

Hello! Could you please refer to some related literature, textbook or examples for the fact that initial conditions don't change the results a lot ?


Thank you in advance!