Anomalous Doppler effects in phononic band gaps.
Doppler effects in periodic acoustic media were studied theoretically and experimentally. Analytical formulas are derived using the Green's function formalism. We found that a far field observer cannot hear the sound inside a band gap from a stationary source, but a moving source can be heard even if the frequency is inside the gap, and the Doppler shifts can be inverted or anomalously large.
Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Xinhua
X
Hu
Zhihong
Z
Hang
Jensen
J
Li
Jian
J
Zi
C T
CT
Chan