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Solution of the three-dimensional Helmholtz equation using ... - cerfacs

Solution of the three-dimensional Helmholtz equation using ... - cerfacs

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Motivations<br />

Wave propagation modelling<br />

<strong>Solution</strong> method components: Iterative method and multigrid<br />

<strong>Solution</strong> strategy<br />

Numerical experiments<br />

Perspectives and conclusions<br />

Continuous problem<br />

Discrete problem<br />

Finite difference frequency domain approach<br />

Finite difference methods<br />

Ω is always box shaped<br />

Second-order finite difference discretization methods on<br />

non-equidistant grids<br />

Seven-point discretization in <strong>three</strong> dimensions<br />

Accuracy requirement for second order schemes<br />

Accuracy requirement for second order discretization: k h ≤ π 5<br />

for 10 points per wavelength<br />

Rule <strong>of</strong> thumb: k h is kept constant to 0.625 × 3 4<br />

e.g. k = 480<br />

induces h = 1<br />

1024<br />

This leads to a large complex sparse linear system !<br />

10/27 Multigrid for geophysics applications

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