The attenuation characteristics of four specially designed mufflers tested on a practical engine setup / George M. Stokes and Don D. Davis, Jr.
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| Format: | Government Document Book |
| Language: | English |
| Published: |
Washington, D.C. :
National Advisory Committee for Aeronautics,
1953.
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| Series: | Technical note (United States. National Advisory Committee for Aeronautics) ;
2943. |
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| Abstract: | This paper presents the results of muffler tests made to evaluate the theoretical resonator-muffler attenuation expression as applied to practical applications. A specific design procedure for the mufflers tested is also included. Four resonator-type mufflers of different attenuation capabilities where designed and tested on a laboratory cold-test setup and a helicopter field-test setup. Good agreement was found between the laboratory experimental data and theory. The field-test results, however, showed that the mufflers attached to the helicopter did not lower the field noise to the extent predicated by theory or the amount measured in the laboratory test. This attenuation reduction is believed to be due in part to the nonfulfillment of the basic theoretical assumptions of low sound pressures and zero flow velocities and in part to the extraneous noise level. Although the theoretically predicted attenuation may not be obtained in practical installations, the results show that the resonator equation can be very useful in the design and development of mufflers. |
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| Item Description: | "May 1953." NACA TN Number 2943. |
| Physical Description: | 30 pages : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references. |
| Action Note: | committed to retain |