/[escript]/trunk/finley/test/python/seismic_wave.py
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Annotation of /trunk/finley/test/python/seismic_wave.py

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Revision 842 - (hide annotations)
Thu Sep 7 05:40:22 2006 UTC (13 years, 7 months ago) by gross
File MIME type: text/x-python
File size: 4803 byte(s)
a little wave propagation simulation
1 gross 842 """
2     seismic wave propagation
3    
4     @var __author__: name of author
5     @var __licence__: licence agreement
6     @var __url__: url entry point on documentation
7     @var __version__: version
8     @var __date__: date of the version
9     """
10    
11     __copyright__=""" Copyright (c) 2006 by ACcESS MNRF
12     http://www.access.edu.au
13     Primary Business: Queensland, Australia"""
14     __license__="""Licensed under the Open Software License version 3.0
15     http://www.opensource.org/licenses/osl-3.0.php"""
16     __author__="Lutz Gross, l.gross@uq.edu.au"
17     __url__="http://www.iservo.edu.au/esys/escript"
18     __version__="$Revision$"
19     __date__="$Date$"
20    
21     from esys.escript import *
22     from esys.escript.linearPDEs import LinearPDE
23     from esys.finley import Brick
24    
25     resolution=4000. # number of elements per m
26     l=80000. # width and length m
27     h=30000. # height in m
28    
29     rho_bedrock=8e3
30     mu_bedrock=1.7e11
31     lambda_bedrock=1.7e11
32    
33     l_x_water=10000 # length of water in x
34     l_y_water=10000 # length of water in y
35     h_water=max(2000,resolution) # depth of water region
36    
37     water_tag=2
38     rho_water=1e3
39     mu_water=0.
40     lambda_water=1.e9
41    
42     d0_sand=10000 # thickness of sand region on surface
43     d_sand=max(2000,resolution) # thickness of sand layer under the water
44    
45     sand_tag=3
46     rho_sand=5e3
47     mu_sand=1.5e10
48     lambda_sand=1.5e10
49    
50    
51     # location and geometrical size of event:
52     xc=[30000.,40000.,10000.]
53     src_radius = 0.1*h
54     # direction of event:
55     event=numarray.array([1.,0.,0.])*1.e6
56     # time and length of the event
57     tc_length=2.
58     tc=sqrt(5.*tc_length)
59     print "event location = ",xc
60     print "radius of event = ",src_radius
61     print "time of event = ",tc
62     print "length of event = ",tc_length
63     print "direction = ",event
64    
65     t_end=22.
66    
67     def getDomain():
68     """
69     this defines a dom as a brick of length and width l and hight h
70    
71    
72     """
73     ne_l=int(l/resolution+0.5)
74     ne_h=int(h/resolution+0.5)
75     print "grid : %s x %s x %s"%(ne_l,ne_l,ne_h)
76     dom=Brick(ne_l,ne_l,ne_h,l0=l,l1=l,l2=h,order=1)
77    
78     fs=Function(dom)
79     x=Function(dom).getX()
80     fs.setTags(sand_tag,wherePositive(x[0]-(l-l_x_water-d0_sand)) \
81     *wherePositive(x[1]-(l-l_y_water-d0_sand)) \
82     *wherePositive(x[2]-(h-h_water-d_sand)))
83     fs.setTags(water_tag,wherePositive(x[0]-(l-l_x_water)) \
84     *wherePositive(x[1]-(l-l_y_water)) \
85     *wherePositive(x[2]-(h-h_water)))
86     return dom
87    
88     def getMaterialProperties(dom):
89     rho =Scalar(rho_bedrock,Function(dom))
90     rho.setTaggedValue(sand_tag,rho_sand)
91     rho.setTaggedValue(water_tag,rho_water)
92    
93     lame_mu =Scalar(mu_bedrock,Function(dom))
94     lame_mu.setTaggedValue(sand_tag,mu_sand)
95     lame_mu.setTaggedValue(water_tag,mu_water)
96    
97     lame_lambda=Scalar(lambda_bedrock,Function(dom))
98     lame_lambda.setTaggedValue(sand_tag,lambda_sand)
99     lame_lambda.setTaggedValue(water_tag,lambda_water)
100    
101     return rho,lame_mu,lame_lambda
102    
103    
104     def wavePropagation(dom,rho,lame_mu,lame_lambda):
105     x=Function(dom).getX()
106     # ... open new PDE ...
107     mypde=LinearPDE(dom)
108     mypde.setSolverMethod(LinearPDE.LUMPING)
109     k=kronecker(Function(dom))
110     mypde.setValue(D=k*rho)
111    
112     v_p=sqrt((2*lame_mu+lame_lambda)/rho)
113     print "v_p=",v_p
114     v_s=sqrt(lame_mu/rho)
115     print "v_s=",v_s
116     dt=(1./5.)*inf(dom.getSize()/v_p)
117     print "time step size = ",dt
118     # ... set initial values ....
119     n=0
120     t=0
121     # initial value of displacement at point source is constant (U0=0.01)
122     # for first two time steps
123     u =Vector(0.,Solution(dom))
124     u_last=Vector(0.,Solution(dom))
125    
126     while t<t_end:
127     print n+1,"-th time step t ",t+dt," max u and F: ",Lsup(u),
128     # ... get current stress ....
129     eps=symmetric(grad(u))
130     stress=lame_lambda*trace(eps)*k+2*lame_mu*eps
131     # ... force due to event:
132     F=exp(-((t-tc)/tc_length)**2)*exp(-(length(x-xc)/src_radius)**2)*event
133     print Lsup(F)
134     # ... get new acceleration ....
135     mypde.setValue(X=-stress,Y=F)
136     a=mypde.getSolution()
137     # ... get new displacement ...
138     u_new=2*u-u_last+dt**2*a
139     # ... shift displacements ....
140     u_last,u=u,u_new
141     # ... save current acceleration in units of gravity and displacements
142     if n%10==0: saveVTK("disp.%i.vtu"%(n/10),displacement=u, amplitude=length(u))
143    
144     t+=dt
145     n+=1
146    
147     if __name__ =="__main__":
148     dom=getDomain()
149     rho,lame_mu,lame_lambda=getMaterialProperties(dom)
150     wavePropagation(dom,rho,lame_mu,lame_lambda)

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