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

Pressure/Density Gradient

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

Like Tree3Likes
  • 2 Post By gfoam
  • 1 Post By gfoam

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 6, 2013, 23:44
Default Pressure/Density Gradient
  #1
New Member
 
TX-Texas
Join Date: Oct 2013
Posts: 10
Rep Power: 12
hicabiye is on a distinguished road
Is there a way to plot either pressure or density gradients in Fluent (Fluid)? Or obtain values for for pressure and density derivatives in respect to x, y and z directions, such as dp-dx, dp-dy and dp-dz?
hicabiye is offline   Reply With Quote

Old   October 8, 2013, 12:36
Default
  #2
Senior Member
 
Gonzalo
Join Date: Mar 2011
Location: Argentina
Posts: 122
Rep Power: 16
gfoam is on a distinguished road
yes, go to Plots under Results, then under Y Axis Function choose derivatives and the tipe of Derivative you want. Also yo have to select the lines over wich you want to calculate the gradients. Hope this helps you. Regards. Gonzalo
AshwaniAssam and hicabiye like this.
gfoam is offline   Reply With Quote

Old   October 9, 2013, 11:43
Default
  #3
New Member
 
TX-Texas
Join Date: Oct 2013
Posts: 10
Rep Power: 12
hicabiye is on a distinguished road
Dear gfoam,

I do not see the "derivative" options under the "Y Axis Function." Do you think that I might be missing particular inputs?
hicabiye is offline   Reply With Quote

Old   October 9, 2013, 14:42
Default
  #4
Senior Member
 
Gonzalo
Join Date: Mar 2011
Location: Argentina
Posts: 122
Rep Power: 16
gfoam is on a distinguished road
I don't know why you can't see that, but here you can see an image of it:
derivatives.png
hicabiye likes this.
gfoam is offline   Reply With Quote

Old   October 13, 2013, 21:13
Default
  #5
New Member
 
TX-Texas
Join Date: Oct 2013
Posts: 10
Rep Power: 12
hicabiye is on a distinguished road
Dear gfoam,

Derivatives is still missing from that section. I do not see it as one of my options. Do you think that I might be missing something in the setup stage?

Since it is not working, is it valid to say that density in respect to the x direction is drho-dx since it is discretized?
hicabiye is offline   Reply With Quote

Old   October 15, 2013, 07:47
Default
  #6
Senior Member
 
Gonzalo
Join Date: Mar 2011
Location: Argentina
Posts: 122
Rep Power: 16
gfoam is on a distinguished road
Hi, I'm confused. If you solved your problem (I mean, if you press Calculate and let the software run) you must see the Results/Plots task page. There you can find the derivatives of velocity and pressure, but there isn't a derivative of density. To plot the derivatives of density you can use CFDPost, but I don't how you can do this in that software. Another option you can use is, export the density along the line you want to, and numerically find the derivatives in a spreadsheet. i hope this helps you. Regards. Gonzalo
gfoam is offline   Reply With Quote

Old   December 5, 2013, 22:17
Default
  #7
New Member
 
TX-Texas
Join Date: Oct 2013
Posts: 10
Rep Power: 12
hicabiye is on a distinguished road
Dear gfoam,

I went ahead and exported the pressure and density data to discretize them as dp/dx and drho/dx; however, I have no idea why derivatives do not show up (see figure). Do you happen to know why?
Attached Images
File Type: png yokmus.png (13.2 KB, 81 views)
hicabiye is offline   Reply With Quote

Reply

Tags
ansys, density, fluent, gradient, pressure

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
WSS and normal velocity gradient for the slanted pipe wanna88 FLUENT 2 October 1, 2012 23:34
vortex cause pressure gradient or pressure gradient induce vortex? fruitkiwi Main CFD Forum 4 June 12, 2012 02:12
can I use static enthalpy gradient to describe dT Jay CFX 0 August 7, 2008 00:01
How to compute gradient for non-orthogonal grids? Paul Hsieh Main CFD Forum 3 November 11, 2003 05:52


All times are GMT -4. The time now is 00:00.