CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Totalpressure Ansys (http://www.cfd-online.com/Forums/cfx/88603-totalpressure-ansys.html)

Leuchte May 21, 2011 08:32

Totalpressure Ansys
 
Hello,

i have a problem with the Totalpressure in Ansys-CFX Post. Ive drawn a Line in the center of my domain and extracted density, velocity and static pressure along this line. I imported the data in excel and calculated the Totapressure by:

p_total=p_static + (Density/2)*(Velocity^2) from my fluid mechanics script;)

The problem is, the calculated totalpressure is very far away from the totalpressure extracted from Ansys along the line. What is my mistake? Do i have to calculate the Totalpressure another way because of compression effects?

regards
Niklas

immortality April 9, 2013 04:57

you should use isentropic relations if your case is compressible.

ghorrocks April 9, 2013 18:56

Also keep in mind that the density, pressure and velocity variables are interpolated in your exported file, but when you use the total pressure variable in CFX it is calculated directly on the control volumes. This means your calculation will have interpolation errors in it. The CFX reported total pressure is more accurate.


All times are GMT -4. The time now is 03:46.