yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> I double-checked scripts/test/periodic-triax-velgrad.py; the reason it
> was shrinking vertically is that there was PeriTriaxController engine
> doing the shrinking. If disabled, shear is pure for the case I
> mentioned.
>
>   
Ok.

> To me it is not clear what is the advantage of multiplying velGrad by
> trsf before applying it, but I don't mind actually, if it works.
>   
Huh?! velGrad/_trsfInc are not multiplied by trsf at any point before 
being used.
They are really applied as they are on real (wrapped) cartesian coordinates.

> Is the velocity gradient what they call like that in
> http://ocw.mit.edu/NR/rdonlyres/Earth--Atmospheric--and-Planetary-Sciences/12-800Fall-2004/C6754086-6D62-4354-BB9A-1E8AEF4B4967/0/lecture5.pdf (sect. 5.4) ?
>
>   
Yes, it is.

Regarding the problem of using velGrad of the step before, I'm not sure 
what is "before". In Scene::moveToNextTimeStep(), engines are called 
after cell->update is called before the engines. Pre-computed values 
should be correct for the current time-step, aren't they?

Bruno

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Chareyre Bruno
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