Wayside noise from high-speed trains is a significant environmental problem that needs to be addressed. It exhibits specific propagation characteristics due to the movement of the sound sources. Consideration of these propagation characteristics allows us to develop more accurate noise prediction models and situation-specific countermeasures. In this presentation, we focus on the effects of the airflow velocity distribution around moving train vehicles on sound propagation. To investigate sound wave propagation, we employed parallel phase-shifting interferometry, an optical technique that enables instantaneous 2-D visualization of sound waves. To simulate a high-speed moving sound source and the airflow around the sound source, a launching facility and a wind-tunnel were used, respectively. From the results of the moving model test and wind tunnel test, we verified the sound propagation characteristics such as shadow zones, wavefront distortion, and trapped sound on the model surface. Based on the additional wind tunnel test, we also investigated sound wave behavior through the airflow distribution, which is closely related to the trapped sound. In future work, we aim to validate these phenomena using the actual high-speed train.
Akutsu et al. (Wed,) studied this question.