How to use ANSYS CFX to get the drag coefficient?
I used CFX to simulation a bluff body. CFX offers viscous force and pressure force,but it doesn't the coefficient. How can I get the coefficient of the bluff body? Please the masterhands help me! Thanks a lot!

Re: How to use ANSYS CFX to get the drag coefficie
Hi,
In CFXPost you can obtain force_x()@Surface, force_y()@Surface and force_z()@Surface. If the velocity is aligned with the xaxis, you could obtain the drag coefficient as Cd = force_x()@Surface / (0.5*Rho*U^2*A) 
Re: How to use ANSYS CFX to get the drag coefficie
Many thanks for you reply! Can you sent the tutorial of drag coefficient?

hi
to find drag coefficient, in the above formulae what is A, is A = length * width * 0.8 
A is a representative area. For bluff bodies that is usually the frontal area by for airfoils they frequently use the planform area. Check you use the right area definition.
But this is very basic stuff which is dicussed in most introductory fluid mechanics books. Go to your library and look it up. 
error help
I know this is quite an old post but I don't know where else to turn..
when I try and do force calculations in CFX i get an error message that says "Only geometries with surface data are allowed for calculating force" what does this mean and how do I generate surface data? Thanks Tom Walker 
It means exactly what it says  you can only calculate force on surfaces. You are trying to calculate force on a point, line or volume body and that is not meaningful.

thank you very much, I can't believe I was over thinking it like that!

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Sir, Kindly tell me how to monitor the value of Cd or Cl... In case of Fluent, we can monitor it and later on, we can also plot the graph of Cd vs time or Cl vs time.... but I am unable to monitor the Drag force or lift force on cylinder while using CFX... Please help 
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I tried to make the expression as show in image... In CEL, I couldnt find the exact way to write formula.. In my case Vel=0.034m/s density=1.185kg/m^3 Projected Area=0.02m^2 Drag forces are in x direction ACtually Even in writing formula in EXPRESSION, it is not possible to separate Force in x and y component for Drag and lift coefficient respectively. 
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2. You should write values along with their dimensions in square brackets. 3. You may use variables names to access their values. Your CEL for Cd may look like that: Code:
2*force_x()@Cylinder / (Projected Area*massFlowAve(Density)@inlet 
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I did it... Thank you again... Actually, In post CFD, there is "force_x" term available while write the formula in EXPRESSION...but in CFX pre, there is only term "force ()@region..."...so I was bit confused how to insert "force_x" component... but now i simply write manually "_x" in available term " force ()@region"... 
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