1 | """Example of shallow water wave equation. |
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2 | |
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3 | This is called Netherlands because it shows a dam with a gap in it and |
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4 | stylised housed behind it and below the water surface. |
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5 | |
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6 | """ |
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7 | |
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8 | ###################### |
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9 | # Module imports |
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10 | # |
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11 | from shallow_water import Domain, Reflective_boundary, Dirichlet_boundary,\ |
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12 | Transmissive_boundary, Time_boundary, Constant_height |
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13 | |
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14 | from mesh_factory import from_polyfile, rectangular |
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15 | from Numeric import array |
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16 | from math import sqrt |
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17 | from least_squares import Interpolation |
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18 | |
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19 | |
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20 | print 'Creating domain' |
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21 | #data_points, _, data_values = from_polyfile('cornell_room_medres') |
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22 | #points, triangles, values = from_polyfile('hires2') |
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23 | data_points, _, data_values = from_polyfile('hires2') |
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24 | |
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25 | |
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26 | #Regrid onto numerically stable mesh |
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27 | # |
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28 | #Compute regular mesh based on resolution and extent of data |
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29 | data_points = array(data_points) |
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30 | pmax = max(data_points) |
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31 | pmin = min(data_points) |
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32 | |
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33 | M = len(data_points) |
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34 | |
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35 | N = int(0.8*sqrt(M)) |
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36 | |
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37 | #print N |
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38 | |
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39 | mesh_points, vertices, boundary = rectangular(N, N, |
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40 | len1=pmax[0]-pmin[0], |
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41 | len2=pmax[1]-pmin[1], |
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42 | origin = pmin) |
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43 | |
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44 | |
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45 | #Compute smooth surface on new mesh based on values from old (regrid) |
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46 | print 'Interp' |
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47 | interp = Interpolation(mesh_points, vertices, data_points, alpha=10) |
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48 | mesh_values = interp.fit(data_values) |
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49 | print 'Len mesh values', len(mesh_values) |
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50 | print 'Len mesh points', len(mesh_points) |
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51 | |
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52 | |
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53 | #Create shallow water domain |
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54 | print 'Creating domain' |
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55 | domain = Domain(mesh_points, vertices) #, boundary) |
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56 | |
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57 | domain.check_integrity() |
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58 | domain.default_order = 2 |
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59 | domain.smooth = True |
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60 | domain.reduction = min #Looks a lot better on top of steep slopes |
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61 | |
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62 | print "Number of triangles = ", len(domain) |
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63 | |
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64 | domain.visualise = False |
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65 | domain.checkpoint = False |
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66 | domain.store = True #Store for visualisation purposes |
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67 | domain.format = 'sww' #Native netcdf visualisation format |
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68 | import sys, os |
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69 | root, ext = os.path.splitext(sys.argv[0]) |
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70 | if domain.smooth is True: |
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71 | s = 'smooth' |
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72 | else: |
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73 | s = 'nonsmooth' |
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74 | domain.filename = root + '_' + s |
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75 | |
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76 | #Set bed-slope and friction |
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77 | manning = 0.0 |
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78 | |
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79 | print 'Field values' |
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80 | domain.set_quantity('elevation', mesh_values) |
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81 | domain.set_quantity('friction', manning) |
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82 | |
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83 | |
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84 | ###################### |
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85 | # Boundary conditions |
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86 | # |
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87 | print 'Boundaries' |
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88 | Br = Reflective_boundary(domain) |
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89 | domain.set_boundary({'exterior': Br}) |
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90 | |
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91 | |
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92 | |
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93 | ###################### |
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94 | #Initial condition |
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95 | # |
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96 | print 'Initial condition' |
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97 | |
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98 | #Define water height as a lump in one corner |
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99 | def height(x, y): |
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100 | from Numeric import zeros, Float |
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101 | |
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102 | N = len(x) |
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103 | assert N == len(y) |
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104 | |
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105 | xmin = min(x); xmax = max(x) |
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106 | ymin = min(y); ymax = max(y) |
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107 | |
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108 | xrange = xmax - xmin |
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109 | yrange = ymax - ymin |
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110 | |
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111 | z = zeros(N, Float) |
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112 | for i in range(N): |
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113 | if x[i] <= xmin + 0.25*xrange and y[i] <= ymin + 0.25*yrange: |
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114 | z[i] = 300 |
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115 | |
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116 | return z |
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117 | |
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118 | domain.set_quantity('level', height) |
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119 | |
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120 | E = domain.quantities['elevation'].vertex_values |
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121 | L = domain.quantities['level'].vertex_values |
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122 | domain.set_quantity('level', E+L) |
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123 | |
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124 | #Evolve |
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125 | for t in domain.evolve(yieldstep = 0.05, finaltime = 5.0): |
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126 | domain.write_time() |
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127 | |
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128 | |
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129 | |
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