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

Discrete ordinates (DO) radiation model-solid angles

Register Blogs Community New Posts Updated Threads Search

Like Tree4Likes
  • 1 Post By hamed1387
  • 1 Post By Svetlana
  • 1 Post By hamed1387
  • 1 Post By Svetlana

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 19, 2017, 15:38
Default Discrete ordinates (DO) radiation model-solid angles
  #1
New Member
 
Hamed
Join Date: Jul 2017
Posts: 8
Rep Power: 9
hamed1387 is on a distinguished road
Hi

I have a very important question. Thanks in advance for your help.

The "ansys fluent theory guide 15.0", on the section"Discrete ordinates radiation model theory" states that:

"The discrete ordinates (DO) radiation model solves the radiative transfer equation (RTE) for a finite number of discrete solid angles, each associated with a vector direction S fixed in the global Cartesian system (x,y,z)."

My question: How many solid angles are there for the bellow beam width conditions? How many solid angles are common, generally?
Theta (deg): 1e06
Phi (deg): 1e06

Thanks so much.
Svetlana likes this.
hamed1387 is offline   Reply With Quote

Old   July 19, 2017, 20:14
Default Unclear; read this?
  #2
Senior Member
 
Svetlana Tkachenko
Join Date: Oct 2013
Location: Australia, Sydney
Posts: 416
Rep Power: 15
Svetlana is on a distinguished road
It is not clear to me what conditions you would like to set. A one million theta or phi does not make sense to me personally. Where did you take that from and in what context?

For an introduction to the solid angle concept, I would recommend https://marine.rutgers.edu/dmcs/ms55...solidangle.pdf . The whole sphere is represented by 4*pi solid angle.
hamed1387 likes this.
Svetlana is offline   Reply With Quote

Old   July 20, 2017, 01:54
Default
  #3
New Member
 
Hamed
Join Date: Jul 2017
Posts: 8
Rep Power: 9
hamed1387 is on a distinguished road
Quote:
Originally Posted by Светлана View Post
It is not clear to me what conditions you would like to set. A one million theta or phi does not make sense to me personally. Where did you take that from and in what context?

For an introduction to the solid angle concept, I would recommend https://marine.rutgers.edu/dmcs/ms55...solidangle.pdf . The whole sphere is represented by 4*pi solid angle.
Thanks for recommending the file. In fact, I selected the default conditions defined in the fluent and would like to know how many solid angles the fluent considers in its default conditions. I want to know what parameters in the fluent determine the quantity of solid angles and how?

In the following, the "ansys fluent theory guide 15.0" gives a description about number of solid angles: https://www.uplooder.net/img/image/9...pixelation.PNG
Svetlana likes this.
hamed1387 is offline   Reply With Quote

Old   July 20, 2017, 02:01
Default
  #4
Senior Member
 
Svetlana Tkachenko
Join Date: Oct 2013
Location: Australia, Sydney
Posts: 416
Rep Power: 15
Svetlana is on a distinguished road
It is shown in the figure provided. A location is determined by dtheta and dphi ranges.






hamed1387 likes this.
Svetlana is offline   Reply With Quote

Old   July 20, 2017, 04:24
Default
  #5
New Member
 
Hamed
Join Date: Jul 2017
Posts: 8
Rep Power: 9
hamed1387 is on a distinguished road
I found that we can determine the number of solid angles in the angular discretization box (theta and phi divisions). In fact, for a 3D model, a number of 8N\phiN\theta solid angles and for a 2D model, a number of 4N\phiN\theta will be solved.
hamed1387 is offline   Reply With Quote

Reply

Tags
beam width, discrete ordinates method, solid angles


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
Discrete Element Method Collision Model sfn Fluent Multiphase 5 May 27, 2018 10:25
Using radiation model for simulation of flat plate solar collector marjanbn FLUENT 1 February 24, 2017 18:22
Error - Solar absorber - Solar Thermal Radiation MichaelK CFX 12 September 1, 2016 06:15
Using radiation model for simulation of flat plate solar collector marjanbn FLUENT 2 March 15, 2015 11:27
Overflow Error in Multiphase Modelling with Two Continuous Fluids ashtonJ CFX 6 August 11, 2014 15:32


All times are GMT -4. The time now is 07:03.