[Pndsc]

I'm scripting a system for automatically changing BC's in simulation runs. Is there a particular significance to variables that are specified with brackets around them, or is it just to denote that they are an Inflow?

[ywang89]

Originally Posted by Pndsc

I'm scripting a system for automatically changing BC's in simulation runs. Is there a particular significance to variables that are specified with brackets around them, or is it just to denote that they are an Inflow?

Hi Chris,

The brackets [ ] in boundary.in imply that the pressure is total pressure. Otherwise it is static pressure. This is usually for the INFLOW BC. When the pressure BC is set to total pressure, the temperature BC at the INFLOW is set to total temperature automatically. Therefore, you don't need to set the total temperature BC at the INFLOW.

Thanks,

Yunliang

[mohsinmkhan]

Originally Posted by ywang89

Hi Chris,

The brackets [ ] in boundary.in imply that the pressure is total pressure. Otherwise it is static pressure. This is usually for the INFLOW BC. When the pressure BC is set to total pressure, the temperature BC at the INFLOW is set to total temperature automatically. Therefore, you don't need to set the total temperature BC at the INFLOW.

Thanks,

Yunliang

Sir, I am having one doubt regarding that, for inflow boundary : If we check the total pressure and give pressure.in file instead of mentioning pressure value, we cannot give mass flow value under velocity boundary condition. Then in this case how can we decide or know at what flow rate inflow is happening and how can we vary the flow rate in such case where we are give pressure rate curve..??

[ksrivast]

Greetings,

For subsonic flows, you can have a DIRICHLET/specified boundary condition for either the pressure or the velocity. The other should be Neumann. MASS FLOW is a special dirichlet condition for velocity, and thus cannot be provided along with a pressure profile for your INFLOW boundary.

If you have specified a pressure profile for the INFLOW, you can always obtain the corresponding mass flow rates through the INFLOW in mass_avg_flow.out. Considering a simple example of flow through straight pipe, this flow rate will vary if either the pressure at INFLOW or that at OUTFLOW is varied.

Hope this helps,

Sincerely,