Volume 125, Issue 3, March 2009
Index of content:
- STRUCTURAL ACOUSTICS AND VIBRATION 
125(2009); http://dx.doi.org/10.1121/1.3068450View Description Hide Description
In this manuscript, a method is introduced for the evaluation of Fourier wavenumber decompositions on vibrating surfaces for spatial-spectral analysis. Whereas typical Fourier analysis is restricted to geometries that are separable for meaningful interpretations of the corresponding wave motion, this approach allows for conformal spectral analysis along curved surfaces. This is accomplished by restricting the wavevectors to lie within the local tangent to the surface and to be spatially dependent. The theoretical development is presented and it is demonstrated that commonly utilized kernels appropriate for some simple geometries can be recovered. Additionally, this approach is applied in the analysis of the vibration and radiation of a point driven, fluid loaded cone, where the displacements and pressures have been obtained using the finite element method.
125(2009); http://dx.doi.org/10.1121/1.3075613View Description Hide Description
In this paper, the second principle of thermodynamics is discussed in the framework of statistical energy analysis (SEA). It is shown that the “vibrational entropy” and the “vibrational temperature” of sub-systems only depend on the vibrational energy and the number of resonant modes. A SEA system can be described as a thermodynamic system slightly out of equilibrium. In steady-state condition, the entropy exchanged with exterior by sources and dissipation exactly balances the production of entropy by irreversible processes at interface between SEA sub-systems.