The acoustic phase resonances and surface waves supported by a compound rigid grating

Area of Science:

• Acoustics
• Wave phenomena
• Materials science

Background:

• Rigid gratings with periodic structures support various acoustic modes.
• Understanding mode behavior is crucial for acoustic device design.
• Compound gratings offer unique properties due to asymmetric features.

Purpose of the Study:

• To investigate radiative and bound acoustic modes in a compound grating.
• To characterize 'phase' resonances and non-radiative surface modes.
• To compare experimental results with theoretical predictions.

Main Methods:

• Experimental exploration of mode dispersion using specular reflection and angle of incidence.
• Near-field excitation for characterizing non-radiative surface modes.
• Finite element method (FEM) modeling for theoretical validation.

Main Results:

• Identification and characterization of radiative and bound acoustic modes.
• Observation of 'phase' resonances with specific pressure field phase differences.
• Experimental dispersion curves for both radiative and non-radiative modes.

Conclusions:

• The compound grating supports distinct radiative and bound acoustic modes.
• Phase resonances are a key feature of this grating structure.
• Experimental results align well with FEM predictions, validating the model.