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Crossing trains (moving mesh ?)

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Old   May 5, 2016, 11:29
Default Crossing trains (moving mesh ?)
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Clement Mtrl
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Hi everybody,

I need to estimate the overpressure due to the passage of a train on the side of an other like in the picture attached.

But I'm not really sure about the method I should use.

First I was thinking about doing a steady state simulation of just one train and import this results (map fields) on the final analysis.

In this last analysis I would impose a moving mesh and an interface between the 2 meshes (pimpleDyMFoam). But the width of my first analysis should be bigger than the distance between both trains and now I'm a bit confused about the methodology I should use.

If someone know the guidelines I should use to estimate this pressure on the door I will be very thankful.

Have a good day

EDIT : I searched for this kind of case (2 objects moving) and I didn't find anything. Maybe just one train moving twice the speed and a velocity of 1 time the speed for the whole system ??
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Old   May 14, 2016, 17:20
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Since you're looking for a steady state solution (not sure if this is actually the case in "real life"), then a moving mesh will not help you since you'll be getting a transient solution and, of course, never actually achieve steady state. Just set boundary conditions with the velocities of your trains and run your simulation - easy!
Kind regards,
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Old   May 15, 2016, 19:51
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Clement Mtrl
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Hi Opedrofunk,

Thanks for your answer. Yes it could be a great idea but I really believe ther would be a big difference in steady state and transient solution. I will make the steady state but do you have an idea for the transient one ?

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Old   May 16, 2016, 02:34
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Karl-Johan Nogenmyr
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For the transient you can let one train stand still (in your mesh), while the other moves past. In front of the moving train you remove mesh layers (add/remove meshmodifier). In between the trains you can use GGI. This is doable with foam extend, but be prepared for programming your own mesh-class. See movingConeTopo tutorial. Probably you can do it well with OpenFOAM too, using AMI instead of GGI.

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crossing, moving mesh., openfoam, pimpledymfoam, train

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