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-   -   Problem in calculating drag coefficient (http://www.cfd-online.com/Forums/fluent/33159-problem-calculating-drag-coefficient.html)

 Sohail Ahmed March 4, 2004 04:37

Problem in calculating drag coefficient

I am a beginner in using Fluent. Please help me out to calculate the drag and friction coefficients over an aerodynamic body, if I have the results of pressure, temperature and velocity profiles.

 Farooq March 4, 2004 12:55

Re: Problem in calculating drag coefficient

Well its not difficult:

go to report-forces and give the direction vector...for example give 1 for x and 0 for y and 0 for z (3d)....that will be axial force.

Similarly x=0, y=1 and z=0 is Normal force....

In this way for Lift and drag for a body at 10 deg AOA give components as x= cos(10)n y=sin(10).

fluent will automatically report the forces and moments for you.

I hope this solves your problem

Further you might find it helpful to look at the 2nd tutorial in fluent which is modelling external compressible flow on an aerofoil..

Regards Farooq

 Sohail Ahmed March 18, 2004 01:40

Re: Problem in calculating drag coefficient

Thanks Farooq! Can u please help me in defining boundary conditions in a duct flow?

Currently I am defining Inlet Static Temp and Inlet velocity. No condition defined at the outlet boundary. Also, where should I define Inlet Pressure? Does it have to be defined as "Operating Condition", giving the x & y coordinates of the location (inlet / outlet etc.) or it should be defined in " Boundary Conditions", or while I initialize the problem?

Also, please advise whether the solution has to be 'computed from' Inlet Velocity Zone or from 'All Zones'?