# coefficient drag

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 May 17, 2010, 14:52 coefficient drag #1 New Member   Join Date: May 2010 Posts: 4 Rep Power: 9 hello I am new to CFD, conducted an analysis of flow around a vehicle, I want to determine the coefficient of drag and lift the speed is in the z-axis direction, is appropriate to draw "Force Z" in the body of the vehicle and use the maximum value and apply it to find the drag coefficient. such as graphing the drag coefficient? which method should I take? need help!!!! thanks

 May 17, 2010, 18:39 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 14,339 Rep Power: 110 What do you mean by the maximum value of the force Z? The force probably is not steady so the force Z will not be constant - unless you have managed to get a turbulence model to average all the flow back to a steady state, which is unlikely to be accurate.

 May 25, 2010, 08:38 Plot coefficient drag?? #3 New Member   Join Date: May 2010 Posts: 4 Rep Power: 9 My question is how to plot the drag coefficient. Apply this formula: force_z()@BODY / (0.5*density*Velocity^2*Area) I'm new to CFD, I can not plot, I have to do? Sorry my English is not very good many thanks

 May 25, 2010, 19:09 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 14,339 Rep Power: 110 Define a monitor point with the CEL expression. Then you can see how the drag coefficient moves as the run progresses. Or you can do it in CFD-Post.

 February 9, 2012, 04:33 #5 New Member   Join Date: May 2010 Posts: 4 Rep Power: 9 How do you do the CEL expression?? or How could do it in CFD-post? I can't do this expression, I need you help me, please!!!!

 February 9, 2012, 07:28 #6 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 14,339 Rep Power: 110 Put the expression posted above in as a monitor point in a solver run, or put it into the function calculator in CFD-Post.

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