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

Where / how are cell variables evaluated?

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 5, 2018, 13:55
Default Where / how are cell variables evaluated?
  #1
New Member
 
Tyler Richardson
Join Date: Jun 2017
Posts: 26
Rep Power: 5
tricha122 is on a distinguished road
Question is straight forward but here is some background:

I am evaluating an existing UDF (DEFINE_HEAT_FLUX) to calculate the wall HTC. I do not particularly like the results, so I wanted to go and look on a simple pipe problem how the HTC is evaluated.

I can tell that the UDF is using C_U(c0,t0), C_V(c0,t0), and C_W (c0,t0) to calculate the bulk fluid velocity.

As far as I can tell, this is taking the velocity in the cell adjacent to the wall, which very well may be in the boundary layer, and velocity may not represent the bulk fluid velocity.

In order to prove this, I went to look at the velocity distribution through the first element on the wall, and grabbed the velocity at the center of this first element to try and re-do the calculation. I don't really get the right result.

So I am wondering how / where the C_U, C_V, C_W are evaluated such that I can probe them on my X-Y plot to re-calculate the HTC (by hand) and compare to what fluent calculated with the UDF.

Any help would be greatly appreciated
tricha122 is offline   Reply With Quote

Reply

Tags
cell variables, heat transfer, heat transfer coefficient, htc, udf

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
Simulating fire in a tunnel luca1992 OpenFOAM 14 August 16, 2017 14:50
How to determine the direction of cell face vectors on processor patches sebastian_vogl OpenFOAM Programming & Development 1 October 11, 2016 14:17
Profile data to initialize cell zone variables David Christopher FLUENT 0 May 8, 2014 03:12
[snappyHexMesh] snappyhexmesh cell splitted ununiform..2D case sharonyue OpenFOAM Meshing & Mesh Conversion 1 April 23, 2013 00:34
How to determine the direction of cell face vectors on processor patches sebastian_vogl OpenFOAM Running, Solving & CFD 0 October 27, 2009 09:47


All times are GMT -4. The time now is 14:57.