THE SOUND FIELD FROM A POINT-SOURCE ABOVE A STRIPED IMPEDANCE BOUNDARY

The Helmholtz equation and the boundary condition for a point source a bove an infinite plane surface with a striped impedance structure are studied by the use of Cartesian coordinates and Fourier transform tech nique. The corresponding transformed boundary condition is in the gene ral case a singular integral equation of a known type. For a periodic structure of the boundary impedance, this equation can in special case s be written as a Fredholm equation. If the periodic structure consist s of an infinite number of stripes with just two different values of t he impedance the equation is simplified into a form resembling the one for a homogeneous surface. The wave field is calculated for that case .