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Old   June 2, 2012, 18:36
Post Compressible Flow problem
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Rahul Verma
Join Date: Jan 2012
Location: Mumbai
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Hello Everyone,
I am solving compressible problems with pressure correction approach. I have derived pressure correction equation for unsteady compressible case and solved 2-Dimensional shock tube problem with implicit scheme. Full Navier equation is used as governing equation.
This is my first case and it is working for pressure ratio 5 to 15. with both staggered and collocated approach. This case is perfectly working with variation of grid size, relaxation parameter. So this case is perfectly working for me.

Now problem comes,
I am trying to solve this for plane channel flow case(2D fanoo flow).
Here is detail

Boundary condition:

For velocity : Inlet velocity is defined
No slip boundary condition is used for upper and lower wall
For exit boundary i am taking derivative equal to zero. dU/dx=0

For Temp : Inlet Temp is fixed
for walls dT/dy=0
for exit dT/dx=0

For Pressure:
Since we are not using any pressure boundary condition in SIMPLE, i am also not using in my case,
But in compressible case i need boundary pressures and density.
So for this i am using
dP/dy=0 for walls
and dP/dx=0 for inlet and outlet

for density: No boundary condition is required, calculating by gas law p/RT

This is my problem and this is not working.
Same formulation is perfectly working for shock tube case but not giving correct results for channel case

I think there might some issues with boundary because in both cases boundary has changed.

Please let me know what should i do for this
Thanks & Regards,
Rahul Verma
IIT Bombay
verma_rahul is offline   Reply With Quote


boundary conditions, compressible flow, simple algorithm

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