Learning Forum

[Mohamed Ramon]

[Rob]

Please repost the question. 

[Mohamed Ramon]

If i want to make a 2D transient simulation for air flow inside a pipe for about 20 sec, how can i set the time step size and number  of time steps in order to agree with the Courant Number (note that the cell size is 1*1 mm and air velocity is 5 m/s

[CFD_Friend]

Hi Mohammed,

Can you describe your issue? I can only see the title (Transient fluid flow).

[Rob]

OK, so you can calculate the time for the flow to cross one cell. As a starting time step aim for around 1/10 of that value. You then need enough time steps to reach the desired flow time of 20s. 

I assume the 20s is a few residence times of the pipe and that you're monitoring something to determine whether you've reached equilibrium or whatever result you want to see evolve in the data. 

[Mohamed Ramon]

Can we chat on meesenger 

https://www.facebook.com/mohamed.ramon.7?mibextid=AEUHqQ

[Rob]

Staff are only able to communicate via the Forum. 

[Mohamed Ramon]

aha it's okay, I'm sorry