Clever Geek Handbook

We model processes in OpenFOAM and display the results on the web

In this article I will tell you how you can easily, quickly and cheaply assemble your package for modeling fluid dynamics problems in the cloud. I'll do this using a combination of two tools: the OpenFOAM continuum mechanics numerical simulator and the ParaView dataset visualization toolkit.







I am an ordinary developer and am not an expert in this scientific field. I faced this type of tasks for the first time in the framework of the recently held FIT-M 2020 hackathon , where I was lucky enough to participate as a co-organizer and mentor. The experience seemed interesting to me, in particular, because of the opportunity to touch the field of high performance computing (English High Performance Computing), which are often run on supercomputers . I figured out how you can quickly set up the launch of calculations on a server in the cloud and look at the result directly through the browser, even from a tablet or phone!







It seemed to me that there are not so many materials in Russian on the topic of visualizing results on the web, although the topic itself is quite useful and interesting. Hopefully this step-by-step guide will help someone with their very practical daily tasks. Or maybe it will become for someone the first step into a new and interesting field of science.







Barcelona Supercomputing Center - Centro Nacional de Supercomputación

Image taken from Barcelona Supercomputing Center







Disclaimer



I set myself the task of showing the very possibility of quick start-up and adjustment of calculations, to give a starting point, but by no means building a full-fledged web application. There will be no talk about the potential architecture of such solutions, nor the ready-made source code. The solution is on the knee, but fast.







Short introduction



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Application of CFDs to calculate the reduction of fluctuations of the transported fluid

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An example of a mesh mesh and cells

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. - . motorBike tutorial: 3D- . ( , ).







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  2. , SSH . Linux powershell/cmd Windows 10 :







    $ ssh-keygen -t rsa -b 2048


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    • 6 vCPU ( , tutorial-),
    • 12
    • 10 SSD .
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OpenFOAM



  1. SSH , (Linux) powershell/cmd (Windows) :







    $ ssh -i <_> <_>@<_ip_>


    , .







  2. , , OpenFOAM:







    $ sudo sh -c "wget -O - https://dl.openfoam.org/gpg.key | apt-key add -"
$ sudo add-apt-repository http://dl.openfoam.org/ubuntu
$ sudo apt-get update
$ sudo apt-get -y install openfoam8


    , .







  3. . vi:







    $ vi ~/.bashrc


    • , i
    • , : source /opt/openfoam8/etc/bashrc
    • x!


  4. SSH 







    $ exit


  5. Bash:







    $ simpleFoam -help


    , OpenFOAM.











, , /opt/openfoam8/tutorials/incompressible/simpleFoam/







  1. :







    $ cd $HOME
$ sudo mkdir -p $FOAM_RUN
      
      
    
        
        
        
      
    
    
        
        
        
      
      
    
        
        
        
      
    
    
    








  2. $ cd $FOAM_RUN
$ sudo cp -r $FOAM_TUTORIALS/incompressible/simpleFoam/motorBike/ .
$ sudo chmod -R a+rwx motorBike
$ cd motorBike


  3. , :







    $ ./Allrun


    , . output:







    team01@team01:~/OpenFOAM/team01-8/run/motorBike$ ./Allrun
Running surfaceFeatures on /home/team01/OpenFOAM/team01-8/run/motorBike
Running blockMesh on /home/team01/OpenFOAM/team01-8/run/motorBike
Running decomposePar on /home/team01/OpenFOAM/team01-8/run/motorBike
Running snappyHexMesh in parallel on /home/team01/OpenFOAM/team01-8/run/motorBike using 6 processes
Running patchSummary in parallel on /home/team01/OpenFOAM/team01-8/run/motorBike using 6 processes
Running potentialFoam in parallel on /home/team01/OpenFOAM/team01-8/run/motorBike using 6 processes
Running simpleFoam in parallel on /home/team01/OpenFOAM/team01-8/run/motorBike using 6 processes
Running reconstructParMesh on /home/team01/OpenFOAM/team01-8/run/motorBike
Running reconstructPar on /home/team01/OpenFOAM/team01-8/run/motorBike




Allrun. , OpenFOAM, . . , . , ( ):







$ blockMesh <--     
$ decomposePar -copyZero <--       
$ snappyHexMesh -overwrite <--      
$ potentialFoam <--      
$ reconstruct... <--


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numberOfSubdomains simpleCoeffs:







numberOfSubdomains 6;  <--      

method          hierarchical;
// method          ptscotch;

simpleCoeffs
{
    n               (4 1 1);  <--     numberOfSubdomains 
    delta           0.001;
}
...




ParaView – open-source - . ParaView , . , ParaView , . OpenFOAM, . , ParaView , .







ParaView ( desktop), ( web).









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ParaView Visualization Toolkit (VTK), OpenGL MPI, . ParaView Server ( desktop web) . , Python QT. , :







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  2. pvpython, Python.
  3. Paraview Catalyst, . , , - (, , , , ..).
  4. ParaViewWeb – web-framework, ParaView VTK Web- JavaScript. Three.js, VTK.js – VTK JavaScript.


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  3. - ParaView . web- , : Visualizer, LightViz, ArticViewer, SimPut HPCCloud.









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ParaViewWeb



, , . Kitware web- docker-. , , . , . ParaView.







ParaView, Python dockerhub. :







  • ParaViewWeb, Type = pvw
  • GPU , Rendering = osmesa
  • Major Python 2.x.x, Python = py2


, pvw-v5.7.1-osmesa-py2.







  1. Docker :







    $ sudo apt install docker.io
$ export DEMO_HOST=84.201.179.235   <--  IP  
$ export DEMO_PORT=9000 <--     "" 
$ export IMAGE_TO_RUN=kitware/paraview:pvw-v5.7.1-osmesa-py2  <--


  2. demo web-:







    $ mkdir -p demo
$ cd demo
$ curl -OL https://github.com/Kitware/paraviewweb-demo/archive/master.zip
$ unzip master.zip


  3. web- :







    $ sudo docker pull kitware/paraview:pvw-v5.7.1-osmesa-py2


  4. : OpenFOAM:







    $ sudo docker run -v /home/team01/OpenFOAM/team01-8/demo/paraviewweb-demo-master/pvw:/pvw -v /home/team01/OpenFOAM/team01-8/run/motorBike:/data -p 0.0.0.0:9000:80 -e SERVER_NAME="${DEMO_HOST}:${DEMO_PORT}" -e PROTOCOL="ws" -ti ${IMAGE_TO_RUN}


  5. :

    http://84.201.179.235:9000











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$ paraFoam


: *.foam. , ParaView .







GUI , paraFoam "" QT.







, :







$ touch motorBike.foam


, OpenFOAM. ParaViewWeb.













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. , Amazon (AWS Lambda):









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Of course, OpenFOAM and ParaView are not the only engineering simulation software packages available. There are already a lot of them. But due to the complexity of the setup, as a rule, specialists and scientists involved in such calculations simply study one tool and try to apply it in all tasks. If we make the tools more accessible, then I think we will see a lot more applications of modeling in our lives, and this can be very useful. It's not for nothing that there is a proverb: measure seven times, cut once!







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