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Manu May 1, 2002 13:50

Stag Pressure less than static pressure
 
I am modelling a compressible flow model of turbine blade leakage flow. The flow is compressible, transonic and turbulent. I have set stagnation, pressure, symmetry and wall boundaries. The problem is that when the code is run it gives a ratio of stagnation pressure and staic pressure less than 1 at boundary 1(stagnation) message. I am aware that the pressures at the stagnation and pressure boundaries are defined relative to the reference pressure but are they added to the ref. pressure or is that a scaling factor. It seems it is a scaling factor but I am not sure. Similarly for reference temperature is it a scaling factor or is it added to the reference temperature?

john YL May 3, 2002 06:40

Re: Stag Pressure less than static pressure
 
Reference pressure and temperature are added to the relative values, so they are not scaling factors.

As for stagnation problem you have, the initial condition seems to be important: the static pressure at the boundary is extrapolated from interior, and when the solution is too far away from real solution, this may happen.

Anton Lyaskin May 6, 2002 04:10

Re: Stag Pressure less than static pressure
 
Concerning the reference temperature - it is used only inside the code and during postpocessing. All the temperatures that you specify at the boundaries must be ABSOLUTE.


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