Boundary Condition Help

[stefann]

Hello experts:

I have an airfoil test case (with validated data from instrumentation) that I would like to use to validate Code_Saturne.

The given information is as follows:

INLET:
- Total Temperature
- Total Pressure
- Velocity magnitude (with angle)

Outlet:
- Total Temperature (same as inlet total temperature)
- Total Pressure (lower than inlet total pressure)
- Velocity magnitude (with angle)

With this information I calculated inlet/outlet static temperature and pressure.


I am using the compressible flow module with constant gamma.

I should be able to enter in an inlet with pressure/temperature/velocity and a subsonic outlet with back-pressure. This should be enough for the code to determine the mass flow rate and outlet conditions (temperature and velocity). The outlet conditions from the code should match (within allowable error) to the data I have.

I have some confusion about entering boundary conditions into the GUI.

#1 - What is meant 'reference value for total pressure' under reference values? Judging by the default, it looks like the difference between gauge and absolute. Does the default 101325.0 value imply that all pressures are absolute values?

#2 - I use an imposed inlet, as this gives me the option to input a velocity/temperature/pressure. Are the values of temperature and pressure TOTAL or STATIC?

#3 - I use subsonic outlet as my exit. The pressure I would enter here is this TOTAL or STATIC?

#4 - When I get results after solving, I get 'Pressure' cell data. What is meant by 'Pressure', TOTAL/STATIC GAUGE/ABSOLUTE???


Thanks!


Stefan

[Erwan Le Coupanec]

Hello,

1) The reference pressure is the absolute pressure of reference.

In a standard Code_Saturne computation, the pressure is always defined within a constant and in the results, the label pressure refers to gauge pressure.

In compressible however, it is not the case, the label pressure refers to absolute pressure.

At inlet and outlet, the values of pressure you give shouldn't contain a dynamic component, so it makes them static, I presume.

The pressure cell data in the results is then static and absolute.

Regards,

Erwan.