Finding drag coefficient in CFX

February 25, 2008, 01:13

Hi everyone,

Does anyone knows whether there is an option in CFX-post to select so that we can find the drag coefficient for a fluid flow past a body?

Thanks in advance, Ken

February 25, 2008, 06:02

I dont know of any direct way of doing this, however I sum the forces in the X direction on the body in question then use the equation Drag = 0.5 x Density x Velocity^2 x Plan Area x Cd

I have never found out the true accurcy of this but it has been good enough for my applications. It should give a good estimation though.

Steve

February 25, 2008, 17:44

Hi Steve,

As you are using the definition of drag coefficient it is no estimation, it is a direct calculation of the coefficient. Any error you find then is caused by simulation inaccuracy.

Glenn Horrocks

March 12, 2008, 10:57

please give me how to determine drag coeff. and pree coee. i need in my priject.

March 12, 2008, 20:10

As Steven said in the second post.. use the drag coefficient formula. You can get the force from cfx-solver by doing 'Workspace>New Monitor> then force" and select the wall name that you want.

Cheers

February 25, 2008, 01:13	Finding drag coefficient in CFX	#1
Ken Guest Posts: n/a	Hi everyone, Does anyone knows whether there is an option in CFX-post to select so that we can find the drag coefficient for a fluid flow past a body? Thanks in advance, Ken

February 25, 2008, 06:02	Re: Finding drag coefficient in CFX	#2
Steven Guest Posts: n/a	I dont know of any direct way of doing this, however I sum the forces in the X direction on the body in question then use the equation Drag = 0.5 x Density x Velocity^2 x Plan Area x Cd I have never found out the true accurcy of this but it has been good enough for my applications. It should give a good estimation though. Steve

February 25, 2008, 17:44	Re: Finding drag coefficient in CFX	#3
Glenn Horrocks Guest Posts: n/a	Hi Steve, As you are using the definition of drag coefficient it is no estimation, it is a direct calculation of the coefficient. Any error you find then is caused by simulation inaccuracy. Glenn Horrocks

March 12, 2008, 10:57	Finding drag coefficient in CFX	#4
avneesh Guest Posts: n/a	please give me how to determine drag coeff. and pree coee. i need in my priject.

March 12, 2008, 20:10	Re: Finding drag coefficient in CFX	#5
Maga Guest Posts: n/a	As Steven said in the second post.. use the drag coefficient formula. You can get the force from cfx-solver by doing 'Workspace>New Monitor> then force" and select the wall name that you want. Cheers

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