Improved multipole broadband time-domain impedance boundary condition

An improved multipole broadband time-domain impedance boundary condition was developed. The improved multipole impedance model is shown to satisfy the requirement of being real and passive. It also possesses an extra degree of freedom for fitting prescribed impedance data. It is more accurate and efficient in approximating a given liner impedance than the traditional multipole impedance model. The broadband time-domain impedance boundary condition is implemented by a piecewise linear recursive convolution technique. To validate the broadband time-domain impedance boundary condition, an analytical solution involving broadband acoustic wave propagation in two dimensions is derived. Numerical results show good agreement with analytical solutions.