- 著者
- Takao Tsuchiya Yusuke Makino Yu Teshima Shizuko Hiryu
- 出版者
- ACOUSTICAL SOCIETY OF JAPAN
- 雑誌
- Acoustical Science and Technology (ISSN:13463969)
- 巻号頁・発行日
- vol.44, no.2, pp.101-109, 2023-03-01 (Released:2023-03-01)
- 参考文献数
- 28
- 被引用文献数
- 2
This paper reports on the implementation of a moving sound source and receiver with directivity in the two-dimensional finite-difference time-domain (FDTD) method. A two-dimensional fundamental solution of a moving monopole source is theoretically derived. Then, a fundamental solution of a moving dipole source is obtained by differentiating the fundamental solution of a monopole source in space. Finally, the directivity of moving monopole, dipole, and cardioid sources is theoretically derived. Numerical experiments performed on the two-dimensional sound field showed that the effect of moving velocity on amplitude differs for the monopole and dipole sources. Furthermore, it was found that directivity characteristics of dipole and cardioid sources vary depending on the beam steering angle and moving direction. The present method can be accurately applied to the moving sound source and receiver with directivity.
- 著者
- Ikkyu Aihara Yasufumi Yamada Emyo Fujioka Shizuko Hiryu
- 出版者
- 一般社団法人 電子情報通信学会
- 雑誌
- Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)
- 巻号頁・発行日
- vol.6, no.2, pp.313-328, 2015 (Released:2015-04-01)
- 参考文献数
- 14
- 被引用文献数
- 3
A mathematical model is proposed to describe the nonlinear dynamics of the echolocation behavior of a bat during free flight in an enclosed chamber. In the model, a bat dynamically controls its flight and pulse directions (φf and φp respectively), to avoid collision with multiple walls of the chamber; namely, the bat varies φf and φp repulsively from the closest wall, minimizing the difference between φf and φp. Numerical simulation of the model with specific parameter values demonstrates that the bat can successfully fly in the chamber while emitting pulses along the inner periphery of an eight-shaped flight path, which is consistent with the results of a behavioral experiment conducted by using a Japanese house bat (Pipistrellus abramus).