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

Different Drag coefficient

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 28, 2013, 08:26
Question Different Drag coefficient
  #1
New Member
 
Join Date: Nov 2012
Posts: 6
Rep Power: 14
babak.mahjoub is on a distinguished road
Hi everybody.

I am trying to study the flow over a circular cylinder.

Simply put, the problem is I get different drag coefficient (and other coefficients as well) with the same Reynolds number,

Of course each time I change the diameter and velocity, but the Reynolds number remains the same, I though it is supposed to get me the same result.

For instance:

Fluid is air at 20 Celsius, transient flow, 2d, laminar

D= 0.16 u= 0.0095 => Re=100 Drag co. = 0.2323
D= 0.016 u= 0.095 => Re=100 Drag co. = 0.0183
While I find in literatures that this value must be around 1.2

If Reynolds number is not the only determinant factor, how do I validate my data with privious studies, as they just mentiones Reynolds number, not the inlet velocity

Thanks

Last edited by babak.mahjoub; April 29, 2013 at 10:53.
babak.mahjoub is offline   Reply With Quote

Old   April 29, 2013, 08:34
Default
  #2
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 27
RodriguezFatz will become famous soon enough
From what I learned from previous threads here, it could be that your domain is too small, i.e. the distance from inlet to cylinder is too small or the distance from cylinder to outlet. Can you post a picture of your domain?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Reply

Tags
circular cylinder, drag coefficients, reynolds number


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
Drag Coefficient Convergence Problem John FLUENT 18 June 24, 2023 10:22
problem with saving drag coefficient colopolo FLUENT 5 April 12, 2013 11:59
Calculation of Drag Coefficient, Help Please teek22 CFX 1 April 26, 2012 19:41
Drag coefficient for parcels in dieselFoam sebastian_vogl OpenFOAM Running, Solving & CFD 5 December 31, 2008 13:19
Automotive test case vinz OpenFOAM Running, Solving & CFD 98 October 27, 2008 09:43


All times are GMT -4. The time now is 23:36.