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"Basic FSI setup" questions for model creation and post-processing

GPiove
I have some questions about the model creation:
1)     When I create the constraints for the rigid body object and I have to select the application region, I can choose any node without difference?
2)     Why I have to use the function mesh generator? How can I know the number of elements in each direction or the size?
3)     Is possible to create the euler materials without the init cond euler (shape and initial value) but creating a solid and then apply to it the property of the eulerian solid? If yes, there is any difference in the 2 approaches?
Once I created the model and compute the results using Dytran is possible to post process the results with Patran? Because I try to do so but it seems like the cube doesn’t interact with the water surface and the only output that I obtain is the displacement… I’m also interested in the plot of the pressure generated by the crashing.
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    1) Yes that node can be anywhere - it is just for displaying the DOFs defined for the rigid body
    2) This is the easiest approach that allows for fast editing and readjustment without meshing a large number of solid elements that would also slow Patran down. I'm not sure I understand the second part - in the Input Definition you define the box size and number of elements in each direction to give you the element size you are using.
    3) This is the old way of doing and makes it a hassle to edit and select elements for non-simple cases, so we recommend only the new approach
     
    Yes you can post process results in Patran. It is best to create a new database to read in model and results - you would need to bring in each result file set.
  • 0
    Thank you very much for the answer.
    The problem of post processing was that I only read the results but, as you told me, if I read in model and results it works! I can see both the displacement of the structure and all the other parameters regarding the euler materials like pressure.
     
    I'm not sure to understand the mesh generator function... what I get is that it is necessary to obtain a visualization during the post processing because I can see the results of the euler materials in it. So the important thing is that the mesh generator have to be big enough to contain all the structure and a portion of the euler materials. Am I right?
     
  • 0
    Great - yes that's correct the Mesh generator builds the actual fluid mesh during the solver initialisation (instead of doing this in Patran manually like before). Therefore this mesh is the fluid domain and the material shapes are where the material will lie in it where it intersects.
  • 0
    Ok perfect!
    When I set up the analysis and the output requests named "arc_structure" why I have to select dummy for entity type and not lagrangian?
    If I want to know the stresses and the pressure acting on my lagrangian object (the cube) how I have to create the output request?
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    In this example the cube is just a rigid body, so we are not tracking any stress or strain results on it, therefore we can just output the dummy result to create an output file for it to look at its movement. If you want to see the pressure and other fluid variables on the surface of the structure (rigid or deformable) then you can create a ARC output for the Coupling Surface (instead of the Elements or Grids options in the drop down). Then the variables you can choose are pressure etc.
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