Energy flow model considering near field energy for predictions of acoustic energy in low damping medium

The Acoustic Energy Flow Boundary Element Method (AEFBEM) is developed to predict the acoustic energy density and intensity of an engineering system. Up to now, the acoustic energy flow model has been used only for analysis of high frequencies or radiation noise because of plane wave and far-field assumptions. In this research, a new energy flow governing equation that can consider the near field acoustic energy term and spherical wave characteristics is derived successfully to predict the acoustic energy density and intensity of a system in the medium-to-high frequency range. A near field term of acoustic energy in spherical coordinate is added to the relationship between energy density and energy flow. But with the far-field assumption, this term vanishes, so the relationship between energy density and energy flow becomes the same as that of the plane wave. By considering the near field energy term without far-field assumption, the energy density at medium frequencies can be estimated. However, the governing equation has to be numerically manipulated for use in the analysis of complex structures; therefore, the Boundary Element Method (BEM) is implemented. AEFBEM is a numerical analysis method formulated by applying the boundary element method to an acoustic energy flow governing equation. It is very powerful in predicting the acoustic energy density and intensity of complex structures in medium-to-high frequency ranges, and can analyze interior noise and radiating sound. To verify its validity, several numerical results are provided. BEM and AEFBEM were compared with respect to energy density, and the results from both methods were similar. (C) 2010 Elsevier Ltd. All rights reserved.Lee HW, 2008, SHOCK VIB, V15, P33KUTTRUFF H, 2007, ACOUSTICS INTROPark YH, 2006, SHOCK VIB, V13, P137Park YH, 2006, SHOCK VIB, V13, P167Wang A, 2004, J SOUND VIB, V278, P413, DOI 10.1016/j.jsv.2003.06.018KWON HW, 2004, THESIS SEOUL NATL USeo SH, 2003, J SOUND VIB, V259, P1109, DOI 10.1006/jsvi.2002.5118Park DH, 2001, J SOUND VIB, V244, P651, DOI 10.1006/jsvi.2000.3517Le Bot A, 1998, J SOUND VIB, V211, P537Smith MJ, 1997, J SOUND VIB, V202, P375BOUTHIER OM, 1995, J SOUND VIB, V182, P129BOUTHIER OM, 1995, J SOUND VIB, V182, P149KYTHE PK, 1995, INTRO BOUNDARY ELEMELYON RH, 1995, THEORY APPL STAT ENEBOUTHIER OM, 1992, AIAA J, V30, P616NEFSKE DJ, 1989, J VIB ACOUST, V111, P94CREMER L, 1988, STRUCTURE BORNE SOUNMORSE PMC, 1986, THEORETICAL ACOUSTICKINSLER LF, 1982, FUNDAMENTALS ACOUSTIBELOV VD, 1977, SOV PHYS ACOUST+, V23, P115WOHLEVER JC, 1973, J SOUND VIBRATION, V153, P1