Biomedical subjects

C Campos-Pozuelo

Publications and source records attributed to C Campos-Pozuelo.

3 recordsLinked to original sources

PubMed2001

Numerical model for nonlinear standing waves and weak shocks in thermoviscous fluids.

Nonlinear standing waves in a one-dimensional tube are studied numerically by using a finite-difference algorithm. The numerical code models the acoustic field in resonators for homogeneous, thermoviscous fluids. Calculations are performed exclusively in the time domain, and all harmonic components are obtained by one resolution. The fully nonlinear differential equation is written in Lagrangian coordinates. It is solved without truncation. Effects of absorption are included. Displacement and pressure wave forms are calculated at different locations and results are shown for different excitation levels and tube lengths. Amplitude distributions along the resonator axis for every harmonic component are also evaluated. Simulations are performed for amplitudes ranging from linear to strongly nonlinear and weak shock. A very good concordance with classic experimental and analytical results is obtained.

Journal Article↗

PubMed2000

A macrosonic system for industrial processing

The development of high-power applications of sonic and ultrasonic energy in industrial processing requires a great variety of practical systems with characteristics which are dependent on the effect to be exploited. Nevertheless, the majority of systems are basically constituted of a treatment chamber and one or several transducers coupled to it. Therefore, the feasibility of the application mainly depends on the efficiency of the transducer-chamber system. This paper deals with a macrosonic system which is essentially constituted of a high-power transducer with a double stepped-plate radiator coupled to a chamber of square section. The radiator, which has a rectangular shape, is placed on one face of the chamber in order to drive the inside fluid volume. The stepped profile of the radiator allows a piston-like radiation to be obtained. The radiation from the back face of the radiator is also applied to the chamber by using adequate reflectors. Transducer-chamber systems for sonic and ultrasonic frequencies have been developed with power capacities up to about 5 kW for the treatment of fluid volumes of several cubic meters. The characteristics of these systems are presented in this paper.

Journal Article↗

PubMed2000

Numerical modeling of high-power ultrasonic systems: current status and future trends

Numerical models of high power ultrasonic systems are usually based on finite element or boundary element methods. The basic physical models are linear and rely upon the theory of elasticity, the constitutive law of piezoelectricity and the theory of linear acoustics. They are only valid at low drive level. Some recent developments include nonlinearities of the transduction mechanism and of the propagation medium. In this paper, standard and advanced numerical models are discussed and illustrated by several application examples of high power ultrasonics.

Journal Article↗