5 Implementation of the Rayleigh Integral Method
In this section an implementation of the Rayleigh Integral
Method is described. The plate is of arbitrary shape and is assumed
to be discretised into a set of planar triangles, as illustrated in
figure 2.
The normal velocity distribution on the plate is described
simply by its value at the vertices of the triangles,
the interpolation points. The basis functions
c1, c2, ..., cn
are the pyramid functions,
as illustrated in figure 3. The points p1, p2,
... pn are the vertices of the triangular elements.
As input, the subroutine accepts a description of the geometry of the
plate (made up of triangles), the coordinates of selected points in the
exterior (where the sound pressure is required), the wavenumbers under
consideration and a description of the normal velocity distribution
at each wavenumber. As output, the subroutine gives, for each wavenumber,
the acoustic intensity at the vertices of the triangles that make up the
approximate plate, the sound power, the radiation ratio and the sound
pressure at the prescribed exterior points.
