velocity outlet (or mass flow outlet) boundary condition

Prabin Pradhananga_22497

Hello experts,

 

I have been working on a problem that requires me to use velocity or mass flow outlet boundary condition. Is it possible to do so in any Altair products? Or, if this feature is not available in the GUI, is it possible to do modify the input file and use it?

 

Thanks.

acupro

Prabin Pradhananga_20428 said:

Thank you for your reply.

 

I was able to do as you stated earlier. But the thing is that when I used advanced boundaries, I was not able to get the surface output (integrated) values for that outlet.

When you apply Advanced Boundaries settings, it removes the surface from the 'standard' boundaries.  You can define Surface Monitors (Surface Output) from the Solution ribbon.

My typical recommendation:

Create a Surface Monitor for the Surface Output, and to get the surface set definition/name.

Advance Boundaries > Surface Integrated Condition (SIC) to specify mass flow rate (positive value exits domain, negative value enters domain)

Manually edit the input file to add Simple Boundary Condition type = outflow for that outlet surface - this takes care of the rest of the boundary condition set.

James Lewis

Hi Prabin,

 

You can try Advance Boundaries conditions --> NBC (node boundary condition) to setup for that surface.

 

 

Prabin Pradhananga_22497

James Lewis said:

Hi Prabin,

 

You can try Advance Boundaries conditions --> NBC (node boundary condition) to setup for that surface.

 

 

Thank you for your reply.

 

I was able to do as you stated earlier. But the thing is that when I used advanced boundaries, I was not able to get the surface output (integrated) values for that outlet.

acupro

Prabin Pradhananga_20428 said:

Thank you for your reply.

 

I was able to do as you stated earlier. But the thing is that when I used advanced boundaries, I was not able to get the surface output (integrated) values for that outlet.

When you apply Advanced Boundaries settings, it removes the surface from the 'standard' boundaries.  You can define Surface Monitors (Surface Output) from the Solution ribbon.

My typical recommendation:

Create a Surface Monitor for the Surface Output, and to get the surface set definition/name.

Advance Boundaries > Surface Integrated Condition (SIC) to specify mass flow rate (positive value exits domain, negative value enters domain)

Manually edit the input file to add Simple Boundary Condition type = outflow for that outlet surface - this takes care of the rest of the boundary condition set.

Prabin Pradhananga_22497

acupro_21778 said:

When you apply Advanced Boundaries settings, it removes the surface from the 'standard' boundaries.  You can define Surface Monitors (Surface Output) from the Solution ribbon.

My typical recommendation:

Create a Surface Monitor for the Surface Output, and to get the surface set definition/name.

Advance Boundaries > Surface Integrated Condition (SIC) to specify mass flow rate (positive value exits domain, negative value enters domain)

Manually edit the input file to add Simple Boundary Condition type = outflow for that outlet surface - this takes care of the rest of the boundary condition set.

What if I specify 'profiled inflow' at the outlet and use negative value? Does this work and still act as the outflow?

acupro

Prabin Pradhananga_20428 said:

What if I specify 'profiled inflow' at the outlet and use negative value? Does this work and still act as the outflow?

It would be similar.  However those inflow types (average velocity, mass flow rate) also adjust a profile to the turbulence quantities.  Neither is exactly ideal, since they both develop a velocity profile.