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

How to input the wall temperature b.c.?

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 7, 2008, 14:14
Default How to input the wall temperature b.c.?
  #1
Jimmy
Guest
 
Posts: n/a
Anton, sorry I start this new message for the same topic.

The wall temperature data are as follows:

X Y Z Wall Temperature 49.79 223.25 -112.42 507.33 47.82 230.65 -133.58 484.47 54.05 228.31 -109.53 492.75 55.76 227.48 -115.26 483.30 42.13 228.70 -133.03 496.40 43.86 225.80 -130.58 494.14 39.81 230.16 -131.58 503.69 47.91 228.30 -112.44 506.67 57.91 229.08 -113.01 484.75 .........

Here X, Y and Z are the coordinates of the measurement points on the surface. Totaly we have more than 100,000 measurement points.

From my understanding, there might be two approaches:

(1) Wall temperature table: I don't know how to set a table for above wall temperature conditions, because these points are located on a 3D surface, not a 2D surface.

(2) User subroutine bcdefw.f: This needs to map the measured temperatures to the surface mesh of Star-CD model. But I don't have a tool to do the mapping for this purpose.

What is your suggestion?

Jimmy

  Reply With Quote

Old   March 7, 2008, 14:18
Default Re: How to input the wall temperature b.c.?
  #2
Jimmy
Guest
 
Posts: n/a
The coordinates and wall temperatures measured on the surface are as follows:

X Y Z Wall Temperature 49.79 223.25 -112.42 507.33 47.82 230.65 -133.58 484.47 54.05 228.31 -109.53 492.75 55.76 227.48 -115.26 483.30 42.13 228.70 -133.03 496.40 43.86 225.80 -130.58 494.14 39.81 230.16 -131.58 503.69 47.91 228.30 -112.44 506.67 57.91 229.08 -113.01 484.75 .........

Sorry for the mess with the first message.

Jimmy
  Reply With Quote

Old   March 8, 2008, 09:20
Default Re: How to input the wall temperature b.c.?
  #3
James
Guest
 
Posts: n/a
You can PMAP as well

Create a mesh with the measured data points as the vertices.

Put a shell on your model surface

Read in the measured data surface and data into Prostar

VAVE the read in shells to get cell data.

PMAP the data

Write out the model surface mesh and data

Write a 6 line program to create a file containing the boundary elements and define one region per boundary

Read back into Prostar

  Reply With Quote

Old   March 11, 2008, 05:36
Default Re: How to input the wall temperature b.c.?
  #4
Anton Lyaskin
Guest
 
Posts: n/a
Ok, so as far as I see, it's more like a cloud of points than regular 3D grid, right? I meen, every value for any coordinate appears only once (you can check it by sorting the data on X, Y and Z)? Then the first idea I have is to write table header like INDEPENDENT X, <Number of point you have>, Y, <Number of point you have>, Z, 0 and try to feed it to ProSTAR. You'll probably have to increase MXSTOR parameter above of the default 200000 value to something like <number of points>*4
  Reply With Quote

Old   March 11, 2008, 05:38
Default Re: How to input the wall temperature b.c.?
  #5
Anton Lyaskin
Guest
 
Posts: n/a
Sorry, I've messed with the brackets

Table header should be like

INDEPENDENT X, number_of_points, Y, number_of_point, Z, 0

and MXSTOR is number_of_points*4
  Reply With Quote

Old   March 11, 2008, 07:52
Default Re: How to input the wall temperature b.c.?
  #6
Jimmy
Guest
 
Posts: n/a
Hi James,

It looks like this will be quite a lot of work. Previously I used Fluent for this purpose, and it seems much easier.

Now the problem is, how to create the surface mesh from the measured data?

Thanks,

Jimmy
  Reply With Quote

Old   March 11, 2008, 08:39
Default Re: How to input the wall temperature b.c.?
  #7
Jimmy
Guest
 
Posts: n/a
Anton, your method could be more convenient. Here I want to describe the measured data again because the previous post was messed up for some reason:

X Y Z Wall temperature

49.79 223.25 -112.42 507.33

47.82 230.65 -133.58 484.47

54.05 228.31 -109.53 492.75

55.76 227.48 -115.26 483.30

42.13 228.70 -133.03 496.40

43.86 225.80 -130.58 494.14

......

Totally we have 20,000 measurement points which is cooresponding to 20,000 X, Y and Z numbers shown above. Here my quesitons are:

(1) From my understanding, the "number of points" in your message should be 20,000 which is the number of measurement points. Is is right?

(2) Is there any special requirement with the X, Y, Z and Temperature format in the table file?

Thank you very much,

Jimmy

  Reply With Quote

Old   March 11, 2008, 14:41
Default Re: How to input the wall temperature b.c.?
  #8
Anton Lyaskin
Guest
 
Posts: n/a
(1) Yes, 20000 (2) No, it is said that they can have free format. They can even go unsorted.

Looking forward to see whether this will work or not
  Reply With Quote

Old   March 11, 2008, 15:58
Default Re: How to input the wall temperature b.c.?
  #9
Jimmy
Guest
 
Posts: n/a
Anton, I created the table as mentioned before. It seems that Star-CD requires to read in totally 20,000 x 20,000 x 1 (nx=20000, ny=20000, nz=1), but not 20,000 points from the table. It looks like that this table format is still for the volume-distributed points, but not surface-distributed points which is what I want.

Any suggestions?

Jimmy

  Reply With Quote

Old   March 14, 2008, 09:31
Default Re: How to input the wall temperature b.c.?
  #10
Anton Lyaskin
Guest
 
Posts: n/a
Well, I've checked it too and looks you're right. That meens that you'll have to go for user subroutine. And you'll need to code some mapping algorithm into it, like 1) reading coordinates of the boundary, 2) looking for the nearest data points in your data file, 3) somehow interpolating your data to boundary location. And because your data points are scattered, this can be a real pain!
  Reply With Quote

Reply


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
temperature wall yamina.h FLUENT 1 February 28, 2011 13:25
How to input the wall temperature b.c.? Jimmy Siemens 16 March 7, 2008 14:11
ho to input a computed temperature value in a UDF mcb FLUENT 0 March 7, 2007 06:06
About the wall temperature zt_zt FLUENT 3 May 12, 2003 08:09
About fix wall temperature in wall boundary joon Siemens 2 March 10, 2003 01:41


All times are GMT -4. The time now is 00:10.