New question #693485 on Yade:
https://answers.launchpad.net/yade/+question/693485
Hello everyone:
I am a beginner in PFV, i have a bit of problem with water pressure in PFV and
DFNFlowEngine. I am trying to inject water in a cubic rock matrix with
flow.imposeFlux((0.5,0.5,0.5),-0.01). Although the program did not run
incorrectly, I found that there was a large negative water pressure (-7.2e+7pa)
in Paraview. So my question is :
1. Why there is negative water pressure, what is the reason,
2. how to avoid the occurrence of negative water pressure.
3. Is negative water pressure due to a problem with my script.
And There is my code:
##################
from yade import ymport, utils, plot
import math
import random
from pylab import *
print '\nRunning!\n'
PACK='10Kspheres'
intR=1.245
DFN='penny_R0.1'
DENS=2000
YOUNG=20e9
ALPHA=0.12
TENS=40e6
COH=40e6
FRICT=30
KFluid=2.2e9
visc=1.e-3
pFactor=1e-22
slotAperture=1e-5
DENS_FLUID=1000
flowRate=0.001
saveData=10
iterMax=10
saveVTK=10
OUT=PACK+'_PlaneTests'
O.bodies.append(ymport.text('try.txt',color=(.9,.8,.6)))
dim=utils.aabbExtrema()
xinf=dim[0][0]
xsup=dim[1][0]
X=xsup-xinf
yinf=dim[0][1]
ysup=dim[1][1]
Y=ysup-yinf
zinf=dim[0][2]
zsup=dim[1][2]
Z=zsup-zinf
R=0
Rmax=0
numSpheres=0.
for o in O.bodies:
if isinstance(o.shape,Sphere):
numSpheres+=1
R+=o.shape.radius
if o.shape.radius>Rmax:
Rmax=o.shape.radius
Rmean=R/numSpheres
print 'Pre-processing concluded!\n'
print 'X=',X,' | Y=',Y,' | Z=',Z,' \nSphere numbers =',numSpheres,' |
Rmean=',Rmean
O.reset()
def sphereMat(): return
JCFpmMat(type=1,density=DENS,young=YOUNG,poisson=ALPHA,tensileStrength=TENS,cohesion=COH,frictionAngle=radians(FRICT),
jointNormalStiffness=YOUNG/(pi*Rmean),jointShearStiffness=ALPHA*YOUNG/(pi*Rmean),jointTensileStrength=0.,jointCohesion=0.,jointFrictionAngle=radians(FRICT),jointDilationAngle=radians(0))
def wallMat(): return
JCFpmMat(type=0,density=DENS,young=YOUNG,frictionAngle=radians(0))
mn,mx=Vector3(xinf+0.1*Rmean,yinf+0.1*Rmean,zinf+0.1*Rmean),Vector3(xsup-0.1*Rmean,ysup-0.1*Rmean,zsup-0.1*Rmean)
walls=utils.aabbWalls(oversizeFactor=1.5,extrema=(mn,mx),thickness=0.1*min(X,Y,Z),material=wallMat)
wallIds=O.bodies.append(walls)
O.bodies.append(ymport.text('try.txt',material=sphereMat,color=(.9,.8,.6)))
import gts
v1 = gts.Vertex(0,0.1,0.8)
v2 = gts.Vertex(0,0.9,0.8)
v3 = gts.Vertex(0.9,0.9,0.2)
v4 = gts.Vertex(0.9,0.1,0.2)
e1 = gts.Edge(v1,v2)
e2 = gts.Edge(v2,v4)
e3 = gts.Edge(v4,v1)
f1 = gts.Face(e1,e2,e3)
e4 = gts.Edge(v4,v3)
e5 = gts.Edge(v3,v2)
f2 = gts.Face(e2,e4,e5)
s1 = gts.Surface()
s1.add(f1)
s1.add(f2)
facet = gtsSurface2Facets(s1,wire = False,material=wallMat)
O.bodies.append(facet)
yade.qt.View()
yade.qt.Controller()
execfile('identifBis.py')
flow=DFNFlowEngine(
isActivated=False
,useSolver=3
,boundaryUseMaxMin=[0,0,0,0,0,0]
,bndCondIsPressure = [0,0,0,0,0,0]
,bndCondValue=[0,0,0,0,0,0]
,permeabilityFactor=pFactor
,viscosity=visc
,fluidBulkModulus=KFluid
,clampKValues=False
,jointsResidualAperture=slotAperture
)
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Box_Aabb(),Bo1_Sphere_Aabb(aabbEnlargeFactor=intR,label='Saabb')]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=intR,label='SSgeom'),Ig2_Box_Sphere_ScGeom()],
[Ip2_JCFpmMat_JCFpmMat_JCFpmPhys(cohesiveTresholdIteration=1,label='interactionPhys')],
[Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(smoothJoint=True,neverErase=1,recordCracks=True,Key='recordcrack',label='interactionLaw')]
),
GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=10,timestepSafetyCoefficient=0.8,defaultDt=0.1*utils.PWaveTimeStep()),
flow,
PyRunner(iterPeriod=50,initRun=True,command='saveFlowVTK()',label='saveFlow',dead=1),
NewtonIntegrator(damping=0.4,label="newton"),
]
def saveFlowVTK():
flow.saveVtk(folder='injection')
print('Save flow ', O.iter)
O.step()
SSgeom.interactionDetectionFactor=-1.
Saabb.aabbEnlargeFactor=-1.
flow.isActivated=1
saveFlow.dead=0
O.step()
flow.imposeFlux((0.5,0.5,0.5),-flowRate)
O.dt=1e-7
########################
Best regards and thanks in advance
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