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-   -   Stagnation Pressure in FLUENT (http://www.cfd-online.com/Forums/fluent/98658-stagnation-pressure-fluent.html)

mahi007 March 15, 2012 13:13

Stagnation Pressure in FLUENT
 
Hello all

I am doing analysis of flow past circular cylinder. I am stagnation pressure value at different reynolds numbers. I am taking this from Total pressure infront of cylinder XY plot in FLUENT. Am I right doing this?

Also density value and velocity both equal to 1 in my simulation. Looking at experimental values I am getting nearly 0.5 less for every value. Do I need to add 0.5*density*velocity^2 value to pressure to get stagnation value. If not where I am going wrong?

Thanks

Regards
Mahindra

Kwiaci March 15, 2012 15:42

In FLUENT Total Pressure for incompressible fluids is defined as:
total pressure = static pressure + 0.5*density+velocity^2

Question is what is your methodology of measuring pressure during test? Probably you get there only one component of this equation.

mahi007 March 16, 2012 00:38

Quote:

Originally Posted by Kwiaci (Post 349707)
In FLUENT Total Pressure for incompressible fluids is defined as:
total pressure = static pressure + 0.5*density+velocity^2

Question is what is your methodology of measuring pressure during test? Probably you get there only one component of this equation.

I mean my simulation values are nearly 0.5 less than experimental values. Experimental values are taken from research journals.

Am I correct taking stagnation pressure from total pressure at front of cylinder?

Kwiaci March 16, 2012 07:31

Yes you are. Maybe try to improve mesh in front of cylinder.

mahi007 March 16, 2012 10:56

Quote:

Originally Posted by Kwiaci (Post 349831)
Yes you are. Maybe try to improve mesh in front of cylinder.

I am already using a finer mesh and drag value for this mesh is close to experimental value. Pressure value is not changing much over refinement. Rest of all parameters are good like seperation point etc..

What can I do now?

banty March 16, 2012 11:09

Totel (stagnation) pressure remains constant throughout of domain with compressible or
incompressible flow until shock is present in domain.


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