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

Reference area of 2D axisymmetric geometry

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 4, 2019, 10:00
Unhappy Reference area of 2D axisymmetric geometry
  #1
New Member
 
Shashwat
Join Date: Aug 2019
Posts: 16
Rep Power: 7
Legolas_1204 is on a distinguished road
I am doing a drag analysis of rocket nose cone and I want to use 2D geometry instead of 3D geometry to save time. I know I have to use a 2D geometry with axisymmetric but how can I find the reference area for the geometry. In 3D we can find the reference area using projected area but how to find for 2D axisymmetric body.
Legolas_1204 is offline   Reply With Quote

Old   November 4, 2019, 10:15
Default
  #2
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,740
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
In 2D, the pressures are integrated over the reference depth (default is 1 m), which is another needed input. Now you have a force that acts over an area.

Hint: you can imagine your 2D body being extruded 1m in the third direction and treat it as a 3D body. This analogue doesn't always work because the reference depth need not be 1m and the reference area need not be the projected area.
LuckyTran is offline   Reply With Quote

Old   November 5, 2019, 00:19
Default
  #3
New Member
 
Shashwat
Join Date: Aug 2019
Posts: 16
Rep Power: 7
Legolas_1204 is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
In 2D, the pressures are integrated over the reference depth (default is 1 m), which is another needed input. Now you have a force that acts over an area.

Hint: you can imagine your 2D body being extruded 1m in the third direction and treat it as a 3D body. This analogue doesn't always work because the reference depth need not be 1m and the reference area need not be the projected area.

I understand what you are saying but what you are telling is applicable for planar surface like an aerofoil. But nose cone is a revolving surface so can we take reference depth of 1m in 3rd direction?
Or do we need to revolve the surface 360 degrees and then find the projected area? (In this case, I know that reference area is projected area)
Legolas_1204 is offline   Reply With Quote

Old   November 5, 2019, 02:21
Default
  #4
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,740
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
I missed the part where you mentioned a cone.


In that case, it's integrated over 1 radian
LuckyTran is offline   Reply With Quote

Old   November 5, 2019, 06:12
Default
  #5
New Member
 
Shashwat
Join Date: Aug 2019
Posts: 16
Rep Power: 7
Legolas_1204 is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
I missed the part where you mentioned a cone.


In that case, it's integrated over 1 radian
Okay so from what you are saying if my cone radius is r meters, reference area should be,

(pi * r^2) / 2*pi ??
for 2D geometry?
Legolas_1204 is offline   Reply With Quote

Old   February 16, 2022, 08:25
Default
  #6
Member
 
sina
Join Date: Nov 2021
Posts: 41
Rep Power: 4
sina_sls is on a distinguished road
Quote:
Originally Posted by Legolas_1204 View Post
Okay so from what you are saying if my cone radius is r meters, reference area should be,

(pi * r^2) / 2*pi ??
for 2D geometry?
Hello Shashwat,

I want to compute area in 2D axisymmetric. Do you figure out how can we compute it? Could you please share it?

Best Regards,
sina_sls is offline   Reply With Quote

Old   February 16, 2022, 12:27
Default
  #7
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,740
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
The reference area comes from the 3D representation of the object unless you have a degenerate body such infinite parallel plates where there is no meaning of area.

The pressure being integrated over 1 radian is related to how you go about computing reference area except to understand how the coefficients are calculated using a surface integrated force in 2D.


If you are doing a 2D axissymmetric simulation of a cone, draw the 3D version of the one and get the reference area.
LuckyTran is offline   Reply With Quote

Old   February 16, 2022, 12:40
Default
  #8
Member
 
sina
Join Date: Nov 2021
Posts: 41
Rep Power: 4
sina_sls is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
The reference area comes from the 3D representation of the object unless you have a degenerate body such infinite parallel plates where there is no meaning of area.

The pressure being integrated over 1 radian is related to how you go about computing reference area except to understand how the coefficients are calculated using a surface integrated force in 2D.


If you are doing a 2D axissymmetric simulation of a cone, draw the 3D version of the one and get the reference area.
Thank you for your response, I need area of red part of the picture which i attached , i have to draw 3D form?
bottom of geometry is axis.
Attached Images
File Type: jpg 1.jpg (63.5 KB, 14 views)

Last edited by sina_sls; February 16, 2022 at 14:33.
sina_sls is offline   Reply With Quote

Reply

Tags
axisymmetric 2d fluent, drag coeffcients, reference area

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
compile error about FJMPI chiven OpenFOAM Installation 11 March 31, 2010 06:27
Axisymmetric Reference Area jack1980 FLUENT 0 October 16, 2009 09:34
G95 + CGNS Bruno Main CFD Forum 1 January 30, 2007 00:34
Building OpenFoAm on SGI Altix 64bits anne OpenFOAM Installation 8 June 15, 2006 09:27


All times are GMT -4. The time now is 16:26.