Numerical modeling of waves for a tsunami early warning system

Numerical modeling of waves for a tsunami early warning system
for 360 ◦ is used to solve the MSEs in cylindrical coordinates. The reference
origin r = 0 falls in the middle of the island, while θ = 0 is in corrispondence
with the center of the wave maker boundary and points toward the direction
of the radiated waves.
In order to save computational time, given the model symmetry, only
the upper half of the circular domain was reproduced. The elliptic MSEs
are solved with the finite element method, as for the previously described
experiments, and the linear elements have a maximum size of 0.5 m. The
simulation which solves the elliptic MSE in the half circle of maximum radius
of 150 m have around 605 kDOF and took about one minute to reproduce one
wave frequency component on a AMD opteron 246 2GHz computer equipped
with 4GB of RAM.
real(A)
abs(A)
0.05
0
θ =0 ◦
−0.05
80 100 120 140
angle(A)
0.05
0.04
0.03
0.02
0.01
80 100 120 140
4
2
0
−2
−4
80 100 120 140
r
0.05
0
θ = 180 ◦
−0.05
80 100 120 140
0.05
0.04
0.03
0.02
0.01
80 100 120 140
4
2
0
−2
−4
80 100 120 140
Figure 4.41: Comparison between the elliptic (black lines) and the parabolic
MSE (red lines) solved for the frequency T =3s. The upper panels show
the wave amplitudes, in the middle and lower panels the amplitude absolute
values and phase are shown respectively. The left and right panels refer to
the distance along the directions θ =0 ◦ and θ = 180 ◦
Università degli Studi di Roma Tre - DSIC 87
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