Reference Velocity in Simulation

Linux34
Linux34 Altair Community Member
edited October 2020 in Community Q&A

Hello everyone,

 

i am doing gearbox simulatons with nanoFluidX. I am troubling with the the the reference velocity. In the manual it says it should be the highest expected velocity and it is calculated with the motions speed and then multiplied by an extra safety factor. But when i simulate the gearbox the velocitys  of the fluids (especially of the air) are 6 times higher then the reference velocity. Should i increase the safety factor or is the reference velocity only respectivly the motions speeds?

 

Thanks a lot!

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Answers

  • acupro
    acupro
    Altair Employee
    edited August 2020

    If there are areas/regions where you expect high accelerations, you may want to specify the reference velocity manually rather than letting nFX decide it based on the tip velocity of the gears.  If you also look at the number of air particles with density 1.1 and/or 1.2 X the reference density, that will help to indicate if the higher velocity represents a serious issue.  If there are only a percent or two of the total air particles with high velocity/density, then you may be OK.  There will always be higher velocity in the air than in the oil, probably part of the numerical approach - SPH.

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