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Mathematical Modelling Of�Concentric Hole Cavity Resonator

PROJECT PRESENTATION

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What is a Concentric Hole Cavity Resonator ?

  • We usually call it with a much familiar name as a Muffler.
  • CCR mainly consist of a duct or chamber through which a pipe passes having some hole of specific geometry and dimensions.
  • The position, size, thickness of these hole affect the variation in the sound level of the output sound when compared to the sound level of the input sound.
  • They are used in many automobile industries placed at the end of the exhaust usually called as SILENCER is also a type of CCR.
  • Further discussion will be on the CCR design by us as an initial step of our project.

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Transmission Loss and Reflection Coefficient.

  • Transmission loss is basically the difference between the sound level of the input sound and the sound level of output sound.
  • When used as noise reduction device we try to maximize the transmission loss.
  • Reflection coefficient is the ratio of the reflected wave pressure to that of the incident wave pressure.
  • If wave is completely reflected back with opposite phase then Re = -1,With same phase then Re = 1, is does not reflect then Re=0(Anechoic Termination).
  • Our project is a step toward Designing an Anechoic Termination.

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Chamber Design of CCR

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Expected Positioning of The Chamber

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Mathematical Modelling in MATLAB

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Analysed Results

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Conclusion

  • Main aim of our project was to develop a program which could generate dimensions of a CCR based device for any given set of frequency range and data inputs.
  • The above displayed CCR is a full-fledged sample of our program. Through this program we can design an Anechoic Termination which could be used as a secondary load in the Impedance Tube Setup present in Technical Acoustics Lab which was designed to carry out research funded by DRDO(GTRE).
  • The program in slide 5 is the MAIN EXECUTABLE PROGRAM of the entire program which calls various other functions to give the required output.
  • Graphs shown are mainly representing Transmission loss by different section of the chamber designed for specific frequency range.

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THANK YOU

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The Team

  • Apoorv Tiwari (18je0148)
  • Preet Ashwin Thobhani (18JE0627)
  • Prince Kumar(18je0630)