Fig. 6: Mode shapes of the absolute value of the acoustic pressure, normalized with the maximum value, for the defective cylindrical structure.
From: Acoustic metamaterials characterization via laser plasma sound sources

The resonant frequency of each mode is 2.3 kHz a, 9.1 kHz b, and 13.0 kHz c, as shown in each part of the figure. In d, the modeled middle cross section of the specimen is presented (also shown in Fig. 2b).