An Indirect Boundary Element Technique for Exterior Periodic Acoustic Analysis

The boundary element solution procedure for exterior periodic acoustic problems fails at frequencies associated with the eigenfrequencies of the corresponding interior problems. A new technique is developed to overcome this problem in the indirect boundary element method by expanding the integral equations through the application of multi-valued impedance boundary conditions. The effectiveness of this newly developed UNequal Impedance technique for Qualitative Evaluation of acoustic response (UNIQUE) is demonstrated by applying this procedure for the solution a series of exterior acoustic problems.