In acoustics it is generally assumed that viscous- en thermal boundary layer effects play a minor role in the propagation of sound waves. Hence, these effects are neglected in the basic set of equations describing the sound field. However, for geometries that include small confinements of air or thin air layers, this assumption is not valid. Special models that include viscous and thermal effects are available (for example the Low Reduced Frequency model) but only for a limited number of geometries. To overcome these limitations and provide a solution that can be used for arbitrary geometries, an acoustic finite (2D) element that includes viscous and thermal effects is developed. The model is based on the linearized Navier stokes equations (including shear), the equation of continuity, the equation of state for an ideal gas and the energy equation. The method of weighed residuals is used in combination with a mixed formulation of pressure, temperature and particle velocity degrees of freedom. The results of the developed element code are compared with the results of an existing (analytical) Low Reduced Frequency solution and a viscothermal element that was found in literature.
|Title of host publication||14th International Congress of Sound and Vibration (ICSV14)|
|Subtitle of host publication||9-12 July 2007, Cairns, Australia|
|Place of Publication||Cairns, Australia|
|Publisher||International Institute of Acoustics and Vibration (IIAV)|
|Number of pages||8|
|Publication status||Published - 9 Jul 2007|
|Event||14th International Congress on Sound and Vibration, ICSV 2007 - Cairns, Australia|
Duration: 9 Jul 2007 → 12 Jul 2007
Conference number: 14
|Conference||14th International Congress on Sound and Vibration, ICSV 2007|
|Period||9/07/07 → 12/07/07|
Nijhof, M. J. J., Wijnant, Y. H., & de Boer, A. (2007). An acoustic finite element including viscothermal effects. In 14th International Congress of Sound and Vibration (ICSV14): 9-12 July 2007, Cairns, Australia Cairns, Australia: International Institute of Acoustics and Vibration (IIAV).