Implementation of the Uniform Theory of Diffraction in the Phased Beam Tracing Method

The phased beam tracing method (PBTM), which introduces the phase information into the geometrical acoustic technique, has a definite advantage in simulating the interference of waves at medium frequencies in an enclosed space. Generally, the diffraction effect cannot be included due to the straight propagation of triangular beams. However, the diffraction should be considered in, particularly, near corners, edges, and obstacles at low frequencies. To resolve the problem, the uniform theory of diffraction (UTD) was integrated into the PBTM to predict the low frequency response near a step discontinuity. Using the UTD, we could remove the singularity in the diffraction coefficient near shadow and reflection boundaries. Single and double diffraction were included to correct the conventional PBTM results at low frequencies. The simulation showed a good agreement with previous research and the measurement. The simulation shows a good agreement with previous work and measurement. It is though that the PBTM combined with the UTD can be a fast and efficient acoustic prediction tool in an enclosure at low and mid frequencies.