Moving piston simulation

Rodrigo Padilla_21991
Rodrigo Padilla_21991 Altair Community Member
edited October 2020 in Community Q&A

Hello, i want to try and do a moving piston simulation using acusolve, I attached a drawing of how it moves, I want to see how the air enters the chamber and fills it up to see the pressure behaviour.

 

My question is, where can I find information on how to set up a mesh that moves the face of the piston in the direction specified adding volume to the initial volume (like an extrusion of the mesh) and place a .csv file that tells the motion of said piston in the domain.

 

Many thanks!

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Answers

  • acupro
    acupro
    Altair Employee
    edited April 2020

    What do you know about the motion?  Do you know position (or translation) as a function of time - or do you know velocity as a function of time?  Can you send/attach that data file with the motion information?  This will be simplest with specified mesh motion - using a translation mesh motion with a multiplier function.

  • Rodrigo Padilla_21991
    Rodrigo Padilla_21991 Altair Community Member
    edited April 2020

    I have an excel file that gives me the position vs crank angle, I attach it here

    Unable to find an attachment - read this blog

  • Rodrigo Padilla_21991
    Rodrigo Padilla_21991 Altair Community Member
    edited April 2020

    What do you know about the motion?  Do you know position (or translation) as a function of time - or do you know velocity as a function of time?  Can you send/attach that data file with the motion information?  This will be simplest with specified mesh motion - using a translation mesh motion with a multiplier function.

    Any information about how i can do this????

  • acupro
    acupro
    Altair Employee
    edited April 2020

    The simplest way to do this is with a sinusoidal multiplier function applied to the mesh motion.  I've attached an example AcuConsole database (along with the resultant .inp file) that you can run and review.  Notice the mesh motion has a translation velocity of 1.0, then the translation variable is set to Multiplier Function.  In this fashion, the value of the multiplier function at the given time becomes the translation displacement.

     

    You could also do this with a piecewise linear multiplier function where column 1 is the time and column 2 is the desired mesh displacement - still with the mesh motion set the same as above - with 1.0 translation velocity in the desired direction.

     

    You can also contact your local Altair Mexico support team.

    Unable to find an attachment - read this blog

  • Rodrigo Padilla_21991
    Rodrigo Padilla_21991 Altair Community Member
    edited April 2020

    Thank you for the information acupro! I'll try and work it out!

  • acupro
    acupro
    Altair Employee
    edited April 2020

    Also make sure to review the nodal boundary condition with mesh-x-displacement.  This is how the other mesh nodes are adjusted relative to the moving piston face.  The node set includes all the nodes in the mesh, but it could also include only those nodes that you would like to move.

  • Rodrigo Padilla_21991
    Rodrigo Padilla_21991 Altair Community Member
    edited April 2020

    I am Trying to open now the simulation to review the set up that you suggested but encountered this error, do you know what it is??

     

    image.png.05c138957604c8f849e034b038c1ff23.png

  • acupro
    acupro
    Altair Employee
    edited April 2020

    Which version of AcuConsole (AcuSolve) are you running?  (This was built using the current release version 2019.1.)  Not sure if some language/region settings in Windows could cause that.  You also have the .inp from the zip file.  Have you contacted Altair Mexico for help yet?  55.56.58.68.09

  • Rodrigo Padilla_21991
    Rodrigo Padilla_21991 Altair Community Member
    edited April 2020

    I think is because im using 2018 version not 2019. thanks for the help.

  • Rodrigo Padilla_21991
    Rodrigo Padilla_21991 Altair Community Member
    edited April 2020

    Yeah I think is because of the version, because I couldn´t even import the .inp file, can you save the files in a 2018 version format or something?

     

    image.png.6bdc1a967e41b5aee504760792b0513c.png

     

    Thanks a lot!

  • acupro
    acupro
    Altair Employee
    edited April 2020

    Importing the .inp would also require the mesh files (MESH.DIR).  If you are current Altair customers with HyperWorks units you can download the current release version and try opening the AcuConsole database with the current version.