Analysis of thermal and viscous boundary layers in acoustic absorption by metallic foam
| Autor: | David J. Bamford, Elizabeth A. Magliula, Mark J. Cops, J. Gregory McDaniel |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010407 polymers
Absorption (acoustics) Materials science Acoustics and Ultrasonics Boundary (topology) Mechanics 01 natural sciences Finite element method 0104 chemical sciences Metal Boundary layer Arts and Humanities (miscellaneous) visual_art Thermal visual_art.visual_art_medium Tomography Porosity |
| Zdroj: | The Journal of the Acoustical Society of America. 146(1) |
| ISSN: | 1520-8524 |
| Popis: | A method for estimating acoustic absorption in foams is presented using a combination of micro-computed tomography, finite element analysis, and boundary layer loss theory. In the method, the foam is assumed to be rigid framed and the viscous and thermal boundary layers at the fluid and frame interface are assumed to be small compared to foam dimensions. The boundary layer losses are approximated using an infinite planar model. The method is demonstrated for a commercially available open-cell metallic foam and allows for absorption to be estimated without determination of any intermediate variables that are required in existing methods. Enhancement of sound absorbing properties by selection of foam properties, such as porosity and pores per inch, is discussed. Furthermore, predicted absorption trends agree with other published models and experimental data. A simplified, two-dimensional geometry is presented in which the assumptions of this method are analyzed. |
| Databáze: | OpenAIRE |
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