Propagation of acoustic waves in a fluid-filled pipe with periodic elastic Helmholtz resonators Project supported by the National Natural Science Foundation of China (Grant Nos. 11372346, 51405502, and 51705529). |
(a) Effective bulk moduli for elastic HR, where the solid, dash-dot, and dotted lines correspond to M = 1, 2, and 4, respectively. (b) Effective bulk modulus for rigid HR. |