/[escript]/trunk/doc/examples/usersguide/wave.py
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Contents of /trunk/doc/examples/usersguide/wave.py

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Revision 1161 - (show annotations)
Wed May 23 04:17:52 2007 UTC (11 years, 9 months ago) by jongui
Original Path: trunk/doc/examples/wave.py
File MIME type: text/x-python
File size: 2702 byte(s)
Made some minor updates to the test.
1 from esys.escript import *
2 from esys.escript.pdetools import Locator
3 from esys.escript.linearPDEs import LinearPDE
4 from esys.finley import Brick
5 from numarray import identity,zeros,ones
6
7 ne=32 # number of cells in x_0 and x_1 directions
8 width=10000. # length in x_0 and x_1 directions
9 lam=3.462e9
10 mu=3.462e9
11 rho=1154.
12 tend=60
13 h=(1./5.)*sqrt(rho/(lam+2*mu))*(width/ne)
14 print "time step size = ",h
15
16 U0=0.01 # amplitude of point source
17
18 def wavePropagation(domain,h,tend,lam,mu,rho,U0):
19 x=domain.getX()
20 # ... open new PDE ...
21 mypde=LinearPDE(domain)
22 mypde.setSolverMethod(LinearPDE.LUMPING)
23 kronecker=identity(mypde.getDim())
24
25 # spherical source at middle of bottom face
26
27 xc=[width/2.,width/2.,0.]
28 # define small radius around point xc
29 # Lsup(x) returns the maximum value of the argument x
30 src_radius = 0.1*Lsup(domain.getSize())
31 print "src_radius = ",src_radius
32
33 dunit=numarray.array([1.,0.,0.]) # defines direction of point source
34
35 mypde.setValue(D=kronecker*rho)
36 # ... set initial values ....
37 n=0
38 # initial value of displacement at point source is constant (U0=0.01)
39 # for first two time steps
40 u=U0*whereNegative(length(x-xc)-src_radius)*dunit
41 u_last=U0*whereNegative(length(x-xc)-src_radius)*dunit
42 t=0
43
44 # define the location of the point source
45 L=Locator(domain,numarray.array(xc))
46 # find potential at point source
47 u_pc=L.getValue(u)
48 print "u at point charge=",u_pc
49
50 u_pc_x = u_pc[0]
51 u_pc_y = u_pc[1]
52 u_pc_z = u_pc[2]
53
54 # open file to save displacement at point source
55 u_pc_data=open('./data/U_pc.out','w')
56 u_pc_data.write("%f %f %f %f\n"%(t,u_pc_x,u_pc_y,u_pc_z))
57
58 while t<tend:
59 # ... get current stress ....
60 g=grad(u)
61 stress=lam*trace(g)*kronecker+mu*(g+transpose(g))
62 # ... get new acceleration ....
63 mypde.setValue(X=-stress)
64 a=mypde.getSolution()
65 # ... get new displacement ...
66 u_new=2*u-u_last+h**2*a
67 # ... shift displacements ....
68 u_last=u
69 u=u_new
70 t+=h
71 n+=1
72 print n,"-th time step t ",t
73 u_pc=L.getValue(u)
74 print "u at point charge=",u_pc
75
76 u_pc_x=u_pc[0]
77 u_pc_y=u_pc[1]
78 u_pc_z=u_pc[2]
79
80 # save displacements at point source to file for t > 0
81 u_pc_data.write("%f %f %f %f\n"%(t,u_pc_x,u_pc_y,u_pc_z))
82
83 # ... save current acceleration in units of gravity and displacements
84 if n==1 or n%10==0: saveVTK("./data/usoln.%i.vtu"%(n/10),acceleration=length(a)/9.81,
85 displacement = length(u), tensor = stress, Ux = u[0] )
86
87 u_pc_data.close()
88
89 mydomain=Brick(ne,ne,10,l0=width,l1=width,l2=10.*width/32.)
90 wavePropagation(mydomain,h,tend,lam,mu,rho,U0)
91

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