Finite-difference time-domain analysis on leak transmission characteristics of narrow gaps

The sound insulation performance of such wall systems as window sashes, doors, and movable partition walls is often affected by sound waves propagating through narrow gaps that exist at their peripheral parts. In this paper, the leak transmission characteristics through narrow gaps existing in the window sash was investigated through numerical and experimental studies. First, the validity of the finite-difference time-domain (FDTD) method with nonuniform-mesh system was confirmed through 1-dimensional and 2-dimensional numerical studies. Second, narrow gaps at the peripheral parts of a window sash were numerically modeled and their leak transmission characteristics were calculated by the 3-dimensional FDTD method. To evaluate the calculation results, they were compared with measurement results of leak transmission characteristics of a real window sash. As a result, numerical results showed good agreement with the experimental results.