Abstract
In recent years many techniques have been developed for ultrasonic characterization of fruit and vegetables in postharvest processes. All have found common macroscopic acoustic parameters: a slow propagation speed and a large absorption. This paper presents a numerical model for elastodynamic simulation applied to the propagation of elastic waves through the orange peel (Citrus sinensis L. Osbeck). In order to do this, apply finite difference time domain (FDTD) techniques based on the linear elastic solids model, taking into account viscous losses. To limit the computational domain have adapted absorbing boundary conditions PML (perfect matched layers) to the spherical coordinate system, so singularities of the system of coordinates are outside the region of interest. In a parallel way, a nondestructive experimental set-up was developed in order to measure the propagation speed and the attenuation of the surface wave at 40 kHz. The ultrasonic test was performed on two different orange cultivars, Navel and Ortanique, each of them composed by seven oranges. The complete dehydration process of each fruit was measured by weighing. The simulation results are in good agreement with the experimental data and shows that the waves that can travel over a relatively long distance trough the orange skin layer (1 cm) are only Rayleigh waves. Finally, the elastic parameters of the orange skin are calculated over time and correlated with the dehydration of the fruit.
BibTeX citation
@inproceedings{Jimenez2010,
author = {Noé Jiménez and Rubén Picó and Francisco Camarena and Javier Redondo and Bernardino Roig and Silvia Adrian},
booktitle = {Tecniacústica 2010: 41º Congreso Español de Acústica y Encuentro Ibérico de Acústica. León, Spain. 13 - 15 October},
doi = {http://www.sea-acustica.es/fileadmin/Leon10/ULT_013.pdf},
editor = {Conference proceedings},
month = {10},
organization = {Sociedad Española de Acústica},
pages = {1-11},
series = {Oral},
title = {Simulación acústica de tejidos vegetales en coordenadas esféricas mediante FDTD},
url = {http://www.sea-acustica.es/index.php?id=526#c628},
year = {2010}
}