CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

How can I get Drag Coeffiecent

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 18, 2006, 08:04
Default How can I get Drag Coeffiecent
  #1
sanxian
Guest
 
Posts: n/a
I am simulating the vortex shedding of 2-d cylinder. But I am wondering if I can get the drag coeffiecent by fluent automatically. Use Solve/Monitor/Force to get the Cd history line is right or not? Thanks for help!
  Reply With Quote

Old   April 18, 2006, 08:50
Default Re: How can I get Drag Coeffiecent
  #2
Cyril
Guest
 
Posts: n/a
That's right !

Make shure you're using the right "references values" like speed, cylender area, ...

Hope that helps !
  Reply With Quote

Old   April 18, 2006, 08:54
Default Re: How can I get Drag Coeffiecent
  #3
sanxian
Guest
 
Posts: n/a
As you said, should I change the reference values as what I have calculated in my case? Thank you for your help? Do you have an MSN? I think maybe we can talk about it furthermore.
  Reply With Quote

Old   April 18, 2006, 09:00
Default Re: How can I get Drag Coeffiecent
  #4
Cyril
Guest
 
Posts: n/a
'dont have msn

About your ref. values, fluent automatically alculate for an area of 1 (I already had the same problem) If you don't change it, you will have very low coefficients. (make shure your mesh is big enough at the rear of your cylinder)

If you've already calculate your drag, you will see very soon if you're right !

good luck
  Reply With Quote

Old   April 18, 2006, 09:26
Default Re: How can I get Drag Coeffiecent
  #5
sanxian
Guest
 
Posts: n/a
In my case, the flow velocity is 1m/s,and the component of the water is the default value in Fluent. The diameter of the cylider is 2m. My case is 2D and I change the density of the reference value, so the Cd value is about 1.25, is more similar as the value shown in many references. I am wondering if I should do other changes and if what I have done is right. Thanks a lot, Cyril. My email address: qdsanxian@hotmail.com Hope to be your friend.
  Reply With Quote

Old   April 18, 2006, 09:30
Default Re: How can I get Drag Coeffiecent
  #6
Cyril
Guest
 
Posts: n/a
Cylinder+2D = 2D axi... (if you didn't, my advice would be to use the 2Daxi model, quicker (half cells), and same accuracy)
  Reply With Quote

Old   April 18, 2006, 10:03
Default Re: How can I get Drag Coeffiecent
  #7
sanxian
Guest
 
Posts: n/a
Ok, thank you. Should I change other reference values in the sheet of "reference value"?
  Reply With Quote

Old   April 18, 2006, 10:13
Default Re: How can I get Drag Coeffiecent
  #8
Cyril
Guest
 
Posts: n/a
Ref values usually upload thmselves when selecting "compute fom".

In 2D area stays as a default value=1.

Others shoul change automatically. Check so that you've got your values and not default ones (speed, ...)

Be shure you've selected your entire model (wall for the cylinder) in the monitor/forces/drag menu.

That should works !

by the way, what's U're name ?
  Reply With Quote

Old   April 18, 2006, 11:27
Default Re: How can I get Drag Coeffiecent
  #9
sanxian
Guest
 
Posts: n/a
Thank you for your help. My name is Liuzhen? Can you pronounce it? I am a Chinese graduated student for doctor courses to study in Korea Maritime University as the exchange student. My former University is Ocean University of China. What about you?

  Reply With Quote

Old   April 18, 2006, 11:32
Default Re: How can I get Drag Coeffiecent
  #10
Cyril
Guest
 
Posts: n/a
My name's Cyril.

Sutdent in an aeronautic engeneering school (The IPSA), in Paris, France.

I've just finished my studies (6 month left, in internship).

glad to meet you.
  Reply With Quote

Old   April 22, 2006, 06:44
Default Re: How can I get Drag Coeffiecent
  #11
Mr.Ta
Guest
 
Posts: n/a
Dear all. I am learning the phenomenon of the flow over a cylinder (especially Vortex shedding) using FLUENT, but i don't know how to model in FLUENT, because i did, but the result is not exact compare to experience. i can't see the vortex shedding even with the Re >=200. help me right now, i need your help. I am a final year student, major of aeronautical engineering, Hanoi university of technology, hanoi, vietnam. Besh wishes.
  Reply With Quote

Old   April 22, 2006, 06:48
Default Re: How can I get Drag Coeffiecent
  #12
Mr.Ta
Guest
 
Posts: n/a
My email is: mrquangngoc@gmail.com Yahoo nick: ngocbkat46 Thanks any your help !!!
  Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pressure drag, friction drag and total drag? Cheng CFX 9 January 26, 2024 14:46
Incorrect Drag and Drag Coefficient for flow over a cylinder ozzythewise Main CFD Forum 8 June 13, 2012 07:24
Drag coefficient for parcels in dieselFoam sebastian_vogl OpenFOAM Running, Solving & CFD 5 December 31, 2008 13:19
Drag formulation REMY FLUENT 0 March 10, 2002 15:05
Inviscid Drag at subsonic, subcritical Mach # Axel Rohde Main CFD Forum 1 November 19, 2001 13:19


All times are GMT -4. The time now is 14:17.