Abstract
A boundary element method is applied to reflection and scattering problems of a cylindrical wave by a defect near a free surface in a two dimensional half space. The source of the cylindrical wave is assumed to be located enough far from a defect. On this assumption, reflected waves at a free surface are easily calculated using a ray theory. With incident and reflected waves as known terms, scattered fields due to the interaction between a defect and a free surface are analyzed using a boundary element method. The proposed method shows much better accuracy than the boundary element method involving only the incident wave as a known term. Application of our method to a simulation of an ultrasonic testing for a thick plate is addressed.
