coefficient drag

JEHERZ · May 17, 2010, 15:52

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

ghorrocks · May 17, 2010, 19:39

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.

JEHERZ · May 25, 2010, 09:38

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

ghorrocks · May 25, 2010, 20:09

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.

JEHERZ · February 9, 2012, 04:33

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!!!!

ghorrocks · February 9, 2012, 07:28

Put the expression posted above in as a monitor point in a solver run, or put it into the function calculator in CFD-Post.

May 17, 2010, 15:52	coefficient drag	#1
JEHERZ New Member Join Date: May 2010 Posts: 4 Rep Power: 16	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 25, 2010, 09:38	Plot coefficient drag??	#3
JEHERZ New Member Join Date: May 2010 Posts: 4 Rep Power: 16	My question is how to plot the drag coefficient. Apply this formula: force_z()@BODY / (0.5densityVelocity^2*Area) I'm new to CFD, I can not plot, I have to do? Sorry my English is not very good many thanks

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May 17, 2010, 19:39		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	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, 20:09		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	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
JEHERZ New Member Join Date: May 2010 Posts: 4 Rep Power: 16	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
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Put the expression posted above in as a monitor point in a solver run, or put it into the function calculator in CFD-Post.