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May 12, 2016, 22:48 |
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#21 | |
Member
Ping Chang
Join Date: Feb 2016
Location: Perth
Posts: 93
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Quote:
I need to count the particle numbers in a specified area? Do you have any hints? |
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October 23, 2017, 08:49 |
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#22 |
New Member
Sandip Wadekar
Join Date: Oct 2014
Posts: 17
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Hello Foamer
I am struggling with lagrangian data sampling for sprayFoam, OF2.2.x version. Basically, i want to evaluate size distribution. So want to calculate particle diameter and velocity during run time. can someone guide me about the easiest way to do that....? Thanks |
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October 23, 2017, 10:40 |
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#23 | |
Assistant Moderator
Bernhard Gschaider
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Quote:
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January 11, 2018, 11:19 |
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#24 | |
Senior Member
Asmaa
Join Date: Mar 2016
Posts: 102
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Quote:
Did you solve this problem? because I have the same now and I don't know what to do. Asmaa |
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January 11, 2018, 16:03 |
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#25 | |
Assistant Moderator
Bernhard Gschaider
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Quote:
I did something like this in PyFoam. See slide 148ff in https://openfoamwiki.net/images/0/05...ForTheLazy.pdf (to fully appreciate it a little knowledge of Pandas would be good)
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January 11, 2018, 16:23 |
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#26 | |
Senior Member
Asmaa
Join Date: Mar 2016
Posts: 102
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Quote:
Thank you very much for your quick reply, the presentation is very usefull and respond to a big part of what I need actually!! But in the other hand I need to extract particles that coincide with a circular surface defined by vector axis and radius and then treat those clouds. Do you have an idea how I can achieve this? Regards, Asmaa |
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January 11, 2018, 18:45 |
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#27 | |
Assistant Moderator
Bernhard Gschaider
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Quote:
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Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request |
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January 12, 2018, 06:13 |
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#28 | |
Senior Member
Asmaa
Join Date: Mar 2016
Posts: 102
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Quote:
Thanks for your reply! yes it is post processing. I want to calculate the sauter mean diameter of particles that coincide with the surface below. Actually I am doing it manually using paraview, by clipping 2 cylinders then slice a plane and extract .csv file than calculate the SMD (SMD=sum(d^3)/sum(d^2)). And I have to vary the radius of cylinders at every sampling. So, I find it really painful that's why I am looking for an automatic way to do it. Any hints will be appreciated! Thanks Asmaa |
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January 12, 2018, 08:34 |
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#29 | |
Assistant Moderator
Bernhard Gschaider
Join Date: Mar 2009
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Quote:
Code:
(data["dist"] **3).sum()/(data["dist"]**2).sum() Reading the particle positions might be problematic with OF 5.0 and v1712 as in those versions the meaning of the positions-file changed.
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January 12, 2018, 09:48 |
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#30 |
Senior Member
Asmaa
Join Date: Mar 2016
Posts: 102
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Thanks for your prompt responses,
[QUOTE=gschaider;677857] Code:
(data["dist"] **3).sum()/(data["dist"]**2).sum() Concerning the output of the cloud positions I don't know how it is built because it contains more than 3 components!! For exemple: (0 0.02311223035 0.01947409306 0.9574136766) 638 96587 1 Actually I am looking in the samplingSurface and cutting plane to see if I can get something through it! Asmaa |
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April 15, 2018, 14:08 |
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#31 |
New Member
Syed Ashruf
Join Date: Nov 2012
Location: Chennai, India
Posts: 11
Rep Power: 13 |
I too have similar issue! Below is a sample 'positions' output
(0.212065 0.0952962 0.536003 0.156636) 376063 1199337 1 (0.0683043 0.384839 0.287326 0.25953) 415092 1305086 2 Not able to understand what is the data (with four components + three numbers thereafter) that OF is trying to dump in the time directory. In my case the file location is time_dir/lagrangian/reactingCloud1/positions Other files like d, U, T etc in the same directory ( time_dir/lagrangian/reactingCloud1/ ) seems to be in typical format and understandable except the 'positions' file. |
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April 15, 2018, 17:27 |
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#32 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Quick'ish question: I received a private message (PM) from ashrufsyed and I came to take a quick look into this... I've learned from the PM that OpenFOAM-dev is being used... But the problem here is that I'm not familiar with how exactly people are retrieving these position files. @ashrufsyed and/or @foamiste: Please provide instructions on which tutorial case I can look into, so that I can check what's going on here?
Because my guess is that the 1st value is a time value for the particle, but it's just a guess based on other cases. The problem is what time exactly is that.
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April 17, 2018, 03:58 |
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#33 |
New Member
Syed Ashruf
Join Date: Nov 2012
Location: Chennai, India
Posts: 11
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Thanks @wyldckat for taking time to have a look at the thread!
I am using fireFoam solver (Version 17.07.24) from the github with the OF-dev (commit 1ff578) For a sample case, you can have a look at the detailedSprinklerInjection case from the github. The 'positions' file is saved in the location time_dir/lagrangian/reactingCloud1/ Regarding the first value, I don't think it correspond to time, because the sample output I posted was for 30s. Also all the four components I get are positive ( at least in my case) whereas my droplet positions actually should have negative x and y values as well |
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April 17, 2018, 04:03 |
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#34 | |
New Member
Syed Ashruf
Join Date: Nov 2012
Location: Chennai, India
Posts: 11
Rep Power: 13 |
Quote:
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April 17, 2018, 05:11 |
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#35 | |
New Member
Syed Ashruf
Join Date: Nov 2012
Location: Chennai, India
Posts: 11
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Quote:
So the question now will be how can we convert these local barycentric coordinates into the global cartesian system? Since the thread suggests that position() variable during the Cloud calculation gives the actual global coordinates, is it possible to get it directly from the OF I/O file itself (in the form an output file) ?
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Thanks Ashruf |
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April 17, 2018, 19:35 |
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#36 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
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Quick answer:
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June 7, 2020, 15:29 |
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#37 |
Member
Jairo A. Gutiérrez S
Join Date: Nov 2014
Posts: 60
Rep Power: 11 |
I've just gotten through all the posts as I have to do something similar. I need to determine particle properties (mass, d, nParcels, velocity) in different positions inside the domain. Don't you think it might be easier to modify the particleCollector.C file to write other properties of the parcels being collected? I am not a very good programmer but if the parcels going through the polygon can be "collected" and removed from the simulation, you can also print to a file some properties of those parcels.
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June 26, 2020, 10:09 |
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#38 |
Senior Member
Join Date: Jun 2020
Posts: 100
Rep Power: 6 |
Hello Bernhard,
I am trying to plot Lagrangian data (particle velocity along a line at a particular time) and I came across your answer regarding sampling Lagrangian data. In your answer you mentioned the following: 1. start paraFoam 2. load the lagrangian data in addition to the "regular" data 3. "Split off" the lagrangian data using the "Extract Block"-filter 4. Open a new view on the result and make that view a "Spreadsheet view". In that view you will see the raw lagrangian data 5. File->Export that view to a CSV-file I am able to extract kinematicloud but I am not able to open a new view over that and get the data (step 4). can you please explain a bit more step 4 (may be some screenshots from paraview)? I will be grateful if you or someone can help me to get the particle velocity data along a line. Best Regards Atul Jaiswal |
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