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.
Hu
Xinhua
X
Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Hang
Zhihong
Z
Li
Jensen
J
Zi
Jian
J
Chan
C T
CT