Which macro yields the absolute pressure value?

shivakumar · April 13, 2015, 06:43

Hi,
From the solution data it is possible to obtain absolute pressure value at each node or cell center. In FLUENT manual I couldn't find the macro for absolute pressure.
Which macro yields the absolute pressure value.?

Thanks in advance

CeesH · April 13, 2015, 06:59

Isn't C_P(c,t) the absolute pressure?

If it is the relative, add the operating pressure to it and you're good to go right?

shivakumar · April 13, 2015, 07:07

Thanks for the reply.

I guess it is a static pressure value but I'm not sure..

But in the solution data, there are absolute, total, static pressure, etc values are available so only confused to access absolute pressure.

CeesH · April 13, 2015, 07:46

Maybe you want to check out the FLUENT user manual, section 7.14.

All pressures that you specify and all pressures computed or reported by ANSYS Fluent are gauge pressures.

So I'd guess the pressure reported by the macro is indeed a gauge pressure.

Then:
P_abs = P_operating + P_gauge. So, to get the absolute pressure, simply add the macro to the operating pressure.

To differentiate a bit more clear:

Static pressure: The static gauge pressure
Dynamic pressure: Velocity pressure (0.5*density*velocity)
absolute pressure: total static pressure; the gauge + operating pressure
total pressure: dynamic + static gauge pressure

Does this answer your question?

shivakumar · April 13, 2015, 12:23

U have solved my doubt. I got it. Thank you very much ..

April 13, 2015, 06:43	Which macro yields the absolute pressure value?	#1
shivakumar Senior Member Join Date: Mar 2013 Location: B'lr Posts: 130 Rep Power: 13	Hi, From the solution data it is possible to obtain absolute pressure value at each node or cell center. In FLUENT manual I couldn't find the macro for absolute pressure. Which macro yields the absolute pressure value.? Thanks in advance

April 13, 2015, 06:59		#2
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	Isn't C_P(c,t) the absolute pressure? If it is the relative, add the operating pressure to it and you're good to go right? shivakumar likes this.

April 13, 2015, 07:46		#4
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	Maybe you want to check out the FLUENT user manual, section 7.14. All pressures that you specify and all pressures computed or reported by ANSYS Fluent are gauge pressures. So I'd guess the pressure reported by the macro is indeed a gauge pressure. Then: P_abs = P_operating + P_gauge. So, to get the absolute pressure, simply add the macro to the operating pressure. To differentiate a bit more clear: Static pressure: The static gauge pressure Dynamic pressure: Velocity pressure (0.5densityvelocity) absolute pressure: total static pressure; the gauge + operating pressure total pressure: dynamic + static gauge pressure Does this answer your question? shivakumar and yijecho like this.

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April 13, 2015, 07:07		#3
shivakumar Senior Member Join Date: Mar 2013 Location: B'lr Posts: 130 Rep Power: 13	Thanks for the reply. I guess it is a static pressure value but I'm not sure.. But in the solution data, there are absolute, total, static pressure, etc values are available so only confused to access absolute pressure.

April 13, 2015, 12:23		#5
shivakumar Senior Member Join Date: Mar 2013 Location: B'lr Posts: 130 Rep Power: 13	U have solved my doubt. I got it. Thank you very much ..