Fig. 1. Conceptual diagram of the miniaturized Helmholtzr esonator applied on the submarine hull.
Fig. 2. The 2D simulation model of the underwater Helmholtz resonators. (a) the basic Helmholtz resonator model. (b), (c) miniaturized Helmholtz resonator models using various degree of space coiling acoustic metamaterial.
Fig. 3. Comparison of the echo reduction between (a)model 1, (b) model 2, and (c) model 3.
Fig. 4. Comparison of the acoustic pressure field between (a) model 1 at 10101 Hz , (b) model 2 at 9251 Hz, and (c) model 3 at 8601 Hz.
Fig. 5. Comparison of the echo reduction between (a) w = 20, (b) w = 25 for model 3.
Fig. 6. The simulation model of the Helmholtz resonator that combines model 3 and scale unit which is changed the model 3’s entrance width of 5 cm.
Fig. 7. Comparison of the echo reduction between (a) model 3, (b) model 4.
Table 1. Dimensions of the simulation model.
Table 2. Material properties of the structure (Air) and the medium (Water) used in this study.
Table 3. Boundary conditions used in this study.
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