Yade

maximum or mean velocity

Asked by JOHN

Good evening,
I am trying to stop my simulation when all the particles have come to a rest.
Is there a good way to find the maximum velocity of the particles?
As i read in your documentation [1] the update scheme uses the mean velocity of the previous step, which could perhaps
do the job as well. Is there a way to access this?

Thank you for your time, I didnt include any code as it is the run of the mill yade example.
Cheers
John

https://yade-dem.org/doc/formulation.html#position

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Jan Stránský (honzik) said : 		#1

Hi John,

something like this?

maxVel = max(b.state.vel.norm() for b in O.bodies)

cheers
Jan

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JOHN (washingmachine) said : 		#2

Hello,
yesm this should do, however I saw that the mean velocity of the previous step is already calculated as a part of the YADE scheme. Is there a way to access this variable? This would propably be more efficient and in my case will be a similar metric to the max velocity
Cheers
John

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Jan Stránský (honzik) said : 		#3

Mean (average) velocity of all particles can be computed similarly:

avgVel = sum(b.state.vel.norm() for b in O.bodies) / len(O.bodies)

"mean velocity during the previous step" from [1] means mean velocity of one specific particle between current and previous time step, not mean velocity of all bodies.
This mean velocity value is simply b.state.vel

chees
Jan

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Bruno Chareyre (bruno-chareyre) said : 		#4

> the mean velocity of the previous step is already calculated as a part of the YADE scheme. Is there a way to access this variable?

Hi,
In Jan's #1 answer b.state.vel.norm() is the norm of the mean velocity of b in the previous step (else what would that be?).
Exactly the one defined in the documentation.
Regards
Bruno

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JOHN (washingmachine) said : 		#5

thanks that was really helpful
Cheers
John