Hi guys,
Hopefully this is an easy question... Once I run the simulation and I have my results, how do I get to the average concentration withinin a volume?
I can select a bunch of elements and get the mean, but this doesn't take into account the volume of the elements, so the mean is skewed. If I try to use Mean Weighted by Volume or Mean Weighted by Mass, I get an error that says I should use the Weight and Center of Gravity Tool. When I run that, it says "No current analysis type can be determined for this model!"
Thanks!
Solved! Go to Solution.
Solved by John_Holtz. Go to Solution.
Solved by John_Holtz. Go to Solution.
The more I look at this, the more it seems like I'm going to have to calculate the volume of the various elements and the average concentration in the volumes myself, based on the data in the database files (elements and nodes).
Hopefully someone can show me an easier way???
T,
The "Mean Weighted by Volume" needs the volume calculation from the "Analysis > Weight and Center of Gravity" calculation, but the Wt&CG calculator does not work with mass transfer. (Not sure why, other than it doesn't work.)
But the file that is needed is the file DS.NCG that Wt&CG creates, and that file is independent of the analysis type. So the work around is:
Presto. The "Mean Weighted by Volume" command will now work in the mass transfer results.
John,
YOU'RE THE MAN!! Works great!
Do you happen to know, is it possible for me to pull this information out of the files programmatically in the same way that I pulled fluid velocity through faces out of the .sfrate or .ufrate files? (I wrote a program in C# to do that.) I'm now pulling concentration averages out load case by case manually, but when I have lots of load cases pulling it out of the files would be much faster.
Thanks again!
Todd
Hi Todd,
(I tried to attach an old (but latest) version of some documentation that describes the binary file formats, etc. The full documentation is 1.82 MB which is slightly too large to fit under the 1.5 MB limit of the Discussion Group. If you can provide your email address, either in a post to the general public here or by clicking AstroJohn link and sending a private message, I will provide the complete compiled help (.CHM) file. Otherwise, these PDF printouts will do.)
I think the general process would be as follows:
The binary result files probably have not changed since the documentation was updated. The documentation for the databases (.dbf located in the .mod folder) may not be up-to-date. I usually use Excel to open them as a dBase file to see what those contain.
Hi John,
Excellent, that sounds about like what I expected I would need to do.
Yeah, from what I've seen the Elements.dbf duplicates nodes for tetrahedrons, for example, so that there are still 8 nodes listed, but some are duplicates.
I was wondering the same thing about the average concentrations, but I'm glad that I don't need to calculate element volumes based on nodal coordinates!
I'll PM you my email address for the .chm file.
Thanks again!
Todd
Hey John,
I have a working program now to read out all of the load cases and calculate the average concentrations in each of my parts. In my current model, I have 5 parts with 96 load cases, so you can imagine that it would take forever to do manually!
A couple things I've noticed. First, just FYI, there is another column in the Elements.dbf table. It is surf_id, located between prop_id and n01. This isn't documented, but it was easy enough to find by connecting to the database via Excel. Oh, and what fun it was figuring out how to connect to the database from my C# application! There's 64 bit vs. 32 bit fun with FoxPro database drivers on a 64 bit Windows 7 install... Since I have 32 bit Office installed, I can only use the 32 bit OLE DB drivers, which means I have to compile my application for x86. Grr! But at least it works now!
The other thing is a question/assumption that I've made. In the Elements.dbf table, the parts (groups) are listed by part number, i.e. the number shown in the GUI. I have several parts, and some of them are suppressed, so the part numbers listed in my table are 1,3,5,7, and 11. But in the various output files, like the .umn and .ncg files, the parts (groups) are listed sequentially and not called out by part number.
So my question is: In what order are the groups listed in the output files? I assumed they would be listed in numerical order, and that works for this particular model. In other words, part #1 was listed first in the output files, followed by part #3, followed by part #5, etc. Can I rely on this, i.e. will they ALWAYS be sorted in numerical order?
Thank you,
Todd
Your assumption about the part ordering in the results is correct. The parts are listed in numerical order.