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[Question #689821]: Problem about O.dt function

 

New question #689821 on Yade:
https://answers.launchpad.net/yade/+question/689821

while i try to use this function  O.dt = .5 * PWaveTimeStep ()

the particles is fall down very slowly. How to make it faster ?

and then i tried to change from O.dt = .5 * PWaveTimeStep () to  become O.dt = 0.001

the particles spread and float.
  
Are there any way to fix it ?

this is my script:

 from yade import pack
import matplotlib.pyplot as plt

idSteel=O.materials.append(FrictMat(young=210e9,poisson=.25,frictionAngle=.8,label="steel"))

O.materials.append(FrictMat(young=3e9,poisson=0.3,frictionAngle=radians(30),density=2600,label='spheres'))



# create rectangular box from boxes (maybe there is some library function, but I did not find it quickly)
cx,cy,cz = 6.3,6.3,6.3 # center of the box
dx,dy,dz = 7.5,7.5,7.5 # half-dimensions of the box
t = 0.25 # half-thickness of walls
left = box((cx-dx-t+1.2,cy+1.2,cz),(t,dy+2*t,cz),fixed=True,wire=True,material="steel")
right = box((cx+dx+t+1.2,cy+1.2,cz),(t,dy+2*t,cz),fixed=True,wire=True,material="steel")
front = box((cx+1.2,cy-dy-t+1.2,cz),(dx,t,cz),fixed=True,wire=True,material="steel")
back = box((cx+1.2,cy+dy+t+1.2,cz),(dx,t,cz),fixed=True,wire=True,material="steel")
bottom = box((cx+1.2,cy+1.2,cz-dz-t+1.2),(dx+2*t,dy+2*t,t),fixed=True,wire=True,material="steel")

left2 = box((cx-dx-t+1.2,cy+1.2,cz*2+2.7),(t,dy+2*t,2.7),fixed=True,wire=True,material="steel")
right2 = box((cx+dx+t+1.2,cy+1.2,cz*2+2.7),(t,dy+2*t,2.7),fixed=True,wire=True,material="steel")
front2 = box((cx+1.2,cy-dy-t+1.2,cz*2+2.7),(dx,t,2.7),fixed=True,wire=True,material="steel")
back2 = box((cx+1.2,cy+dy+t+1.2,cz*2+2.7),(dx,t,2.7),fixed=True,wire=True,material="steel")


top2 = box((cx+1.2,cy+1.2,18+t),(dx,dy,t),fixed=True,material="steel")

psdSizes,psdCumm=[0.0075,0.015,0.0425,.085,.2,.475],[0.,0.195,0.3145,0.6952,.9828,1.]
sp=pack.SpherePack()
# generate randomly spheres with uniform radius distribution
sp.makeCloud((0,0,0),(15,15,1.5),psdSizes=psdSizes,psdCumm=psdCumm,num=10000,seed=1)
# add the sphere pack to the simulation
sp.toSimulation(material='spheres') 

Boxids=O.bodies.append((left,right,back,front,left2,right2,back2,front2,bottom))

O.engines=[
   ForceResetter(),
   InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
   InteractionLoop(
      [Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
      [Ip2_FrictMat_FrictMat_FrictPhys()],
      [Law2_ScGeom_FrictPhys_CundallStrack()]
   ),
   NewtonIntegrator(gravity=(0,0,-9.81),damping=0.4),
   #PyRunner(command='addsphere()',iterPeriod=1000,label='adds'),

]
O.dt=0.5*PWaveTimeStep()



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