SimScale CAE Forum

BC for open atmospheric condition


#1

Hi Simscale family,

I am trying to simulate a train exhaust plume system in the open-atmospheric condition.
What boundary condition would be more appropriate to set in a “sky boundary section”?.

I usually set a wall or symmetry. But now I want to setup an open-atmospheric condition.
Do you have any suggestion?.


#2

Hi @mohamedzaid786!

What you can do is to either increase the box so that it does not influence the flow on the top or use the freestream velocity BC for your faces and set them to a value according to your needs. Hope that makes sense!

@CFD-SQUAD, feel free to correct me and add your own thoughts here.

Best,

Jousef


#3

Hi @mohamedzaid786,

A custom BC with all gradients zero will work. To be safe you should increase the bounding box height.

Cheers.

Regards,
Barry


#4

I am trying to simulate the how exhaust plume affect the inlet vent. The main issue in this project is 2 x inlet vent very close to exhaust vent. Attached my model picture.

Current BC setup:

Exhaust vent = Velocity outlet with 1 passive scalar;
Inlet suction vent = Velocity inlet with 0 passive scalar.

You think this BC is more appropriate for my simulation to continue further or do I need to change my BC to something else.

Please kindly let me know @jousefm

Thanks