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14 Reflecting Boundaries

Assume a flat surface and an incident wave which is propagated by the acoustic wave equation. The finite difference equation, Equation 56, uses a stencil which places a fictitious node or nodes outside the model. These nodes are initially zero and are kept zero for all model time; the superscript n is the time step. This is illustrated in Figure 14 for a flat surface boundary and the second order difference stencil.

Figure 14: Boundary Node Stencil.