Homogeneous Dirichlet

Homogeneous Dirichlet conditions force the wavefield to be zero at the specified boundary.

In the scalar acoustic case, this simply gives

ϕ=0,on Γ,\phi = 0,\quad\text{on~}\Gamma,

and in elastic media, we obtain

u=0,on Γ.u = 0,\quad\text{on~}\Gamma.

It is possible to fix only certain components of the displacement field uu in the elastic case.

Practical Advice

For coupled simulations of waves propagating along a fluid-solid interface, the homogeneous Dirichlet condition is the physically correct condition to describe the "free-surface condition" in water.

Further reading

More information on the practical use of absorbing boundaries can be found on the following pages: