Papers by Carlos E Graffigna
Tecnología HPC como motor de ciencia de la UNdeC
XXIII Workshop de Investigadores en Ciencias de la Computación (WICC 2021, Chilecito, La Rioja), 2021
Precision device for measuring the three dimensional spectral intensity
The Journal of the Acoustical Society of America, 2017
On the basis of processing algorithms developed by the same authors in a companion paper [“On the... more On the basis of processing algorithms developed by the same authors in a companion paper [“On the general connection between wave impedance and sound intensity”, 173rd Meeting of the Acoustical Society of America and the 8th Forum Acusticum, Boston MA, 25-29 June 2017] where the equation between the complex sound intensity and the specific acoustic impedance/admittance has been stated and numerically validated in general form, the block diagram of a possible device for precision measurement of 3D spectral intensity is proposed here. In order to test its functionality, some measurements have been carried out, inside a tube of 28x28 cm2 square section and 4 m long, which was terminated with panels of different materials. Measurements have been carried out at different positions along the tube's axis by means of a 3D pressure-velocity probe below and above the cutoff frequency of the tube so to include also the effects of transversal modes. Preliminary results of such measurements ...
On the general connection between wave impedance and sound intensity
The Journal of the Acoustical Society of America, 2017
This paper presents the generalization to non-monochromatic non-monodimensional fields of the equ... more This paper presents the generalization to non-monochromatic non-monodimensional fields of the equation linking the complex sound intensity to the wave impedance/admittance already introduced with a different form in [D. Stanzial and C. E. Graffigna “On the connection between wave impedance, sound intensity and kinetic energy in monochromatic fields,” accepted for publication on POMA, Dec. 23, 2016]. Computer simulations have been now carried out, both for wave impedance and admittance, in quasi-stationary bi-dimensional waves fields with different reflection coefficients and spectral compositions. It turns out that the equation is validated in all space points of the sound field for each spectral component. This allows primarily to calculate the active intensity vector field as the vector sum of all vector fields obtained as the spectral components of the active intensity and therefore to determine the reactive intensity magnitude by simply subtracting the modulus of the so obtained...
Proceedings of Meetings on Acoustics, 2016
Following a recent article by one of the authors where the concept of complex intensity has been ... more Following a recent article by one of the authors where the concept of complex intensity has been fully developed from the physical point of view and its spectral properties have been highlighted, the present paper focuses on the relationship between sound energy indicators and wave impedance. It will be shown how the specific impedance of monochromatic, plane quasi-stationary and spherical-divergent waves, are related to the complex sound intensity as defined in ["On the physical meaning of the power factor in acoustics", J. Acoust. Soc. Am. 131(1), 269-280 (2012)], suitably normalized to the kinetic energy density. The relationship will be graphically demonstrated to be true along the direction of the active intensity also for 2-D fields with non-vanishing curl.
After a brief introduction to the theory and physical interpretation of Lagrangian force density ... more After a brief introduction to the theory and physical interpretation of Lagrangian force density in general sound fields, this article focuses on its stationary average property providing the general expression of the actionreaction law for acoustic fields. This fundamental property allows to define the tension field of sound, which turns out to be easily measured as the gradient of the average potential energy density. The acoustic tension field has been then analytically calculated and visualized for quasi-stationary wave fields and divergent spherical waves. Moreover 2-D graphics comparing the behaviors of sound energy trajectories and tension fields are here reported.
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Papers by Carlos E Graffigna