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March 19, 2008, 16:23 
DRAG

#1 
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How I can measure the DRAG in any model of Fluent??
For instance a 3d Car model or in 3d wing 

March 19, 2008, 20:53 
Re: DRAG

#2 
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From the menu: Report > Forces...
select all the surfaces of the car or wing (whatever you want to find the drag on) and select the vector direction of the drag force. So, if x points forward (where the car is going) then for drag you'd set the vector direction to: x = 1 y = 0 z = 0 and the result is you get the component of the total force acting on the surfaces you selected  in the rear pointing direction  which is drag! 

March 21, 2008, 13:32 
Re: DRAG

#3 
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remember to set reference area in CD/CL calc and switch to correct reference velocity also


August 29, 2009, 19:06 
Drag On 3D Truck

#4 
New Member
Mrt
Join Date: Mar 2009
Posts: 21
Rep Power: 9 
I calculated drag force and coefficient in the same way that you have mentioned but I obtained 0.313 for 3D truck geometry. In literature, drag coef. value for truck is between 0.60.9. Furtherome, what is wrong with my calculations? I set the ref. values 20 m/s for velocity and 7.2 m2 for frontal area of truck. Also, what is CD/CL calc.for reference are that you mentioned in the last message?
Thanks, Murat 

April 17, 2011, 07:48 

#5  
Member
Aamer Shahzad
Join Date: Mar 2010
Posts: 58
Rep Power: 8 
Quote:
its perfect to use X=1, Y=0 and Z=0, to find drag on a car that is translating in positive X direction..... But how can we calculate drag for a car that is rotating about Y axis...... (i.e initially it is aligned to +X axis and then during rotation it get aligned to +Z axis after rotating 90 degree and then it again gets realigned to +X axis after travelling another 90 degree... 

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