Metasurface For Absorbing Sound By Helmholtz Resonators

Helmholtz resonator shows a robust resonant response if subjected to external excitation for precise frequency.This quality of the Helmholtz resonator can use efficiently attenuate the generation of sound,by assigning the resonator to a variety of geometrical configurations.The first phase of the present investigation focuses on the effects of geometry on the resonant frequency of a Helmholtz resonator.The volume of the resonator varied by adjustment of a piston,which forms the bottom,or end,the surface of the resonator.Furthermore,the effect of cross-sectional area of the mouth(opening)of the resonator is investigated,via employment of different attachment plates at the resonator opening.For all of the above modifications of the Helmholtz resonator,spectral analysis of pressure fluctuations within the resonator indicates the frequency of Helmholtz resonance and the corresponding amplitude of the spectral peak at the resonant state.In the second part of the investigation,the Helmholtz resonator is employed to attenuate the oscillation characteristics of a deep cavity duct,i.e.,a side branch.The Helmholtz resonator is attached to the side of the duct.As for the first part of this investigation,the consequence of variations of geometry and volume of the Helmholtz resonator addressed.Substantial damping of the overall oscillation can attain,as characterised by spectral analysis of the pressure fluctuations at critical locations in the system.The last part of the project,some Helmholtz resonator are employed together to formed a surface.Each Helmholtz resonator is different from other to absorb the different frequency.