流体力学用語集 非線形音響学(Nonlinear acoustics)

Ultrasound (US) was shown to activate persulfate (PS) providing an alternative activation method to base or heat as an in situ chemical oxidation (ISCO) method. The kinetics and mechanism of ultrasonic activation of PS were examined in aqueous solution using an in situ electron paramagnetic resonance (EPR) spin trapping technique and radical trapping with probe compounds. Using the spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), hydroxyl radical (•OH) and sulfate radical anion (SO4•–) were measured from ultrasonic activation of persulfate (US-PS). The yield of •OH was up to 1 order of magnitude greater than that of SO4•–. The comparatively high •OH yield was attributed to the hydrolysis of SO4•– in the warm interfacial region of cavitation bubbles formed from US. Using steady-state approximations, the dissociation rate of PS in cavitating bubble systems was determined to be 3 orders of magnitude greater than control experiments without sonication at ambient temperature. From calculations of the interf...

Kinetics and Mechanism of Ultrasonic Activation of Persulfate: An in Situ EPR Spin Trapping Study.

Design aspects of sonochemical reactors: Techniques for understanding cavitational activity distribution and effect of operating parameters

Review on sonochemical methods in the presence of catalysts and chemical additives for treatment of organic pollutants in wastewater

Continuous and pulsed ultrasound-assisted extractions of antioxidants from pomegranate peel.

Experimental and theoretical investigation of the mean acoustic pressure in the cavitation field.

On the physical origin of conical bubble structure under an ultrasonic horn.

Acoustic cavitation mechanism: A nonlinear model

In this paper, we investigate the problem of ultrasonic propagation in liquids with bubbles. A new numerical algorithm is constructed to solve the acoustic field-bubbles vibration coupled system. For this purpose, a second-order equation written in a volume formulation is considered for bubbles vibration and coupled with the linear nondissipative wave equation, i.e., attenuation and nonlinear effects are supposed to occur exclusively because of the presence of bubbles. Nonlinear characteristics of the phenomenon are particularly analyzed and illustrated. Plane harmonic waves are first considered in a mixture of air bubbles in water, and conclusions about changes in the wave speed, attenuation, harmonic distortion, effective nonlinearity parameter and nonlinear effects with distance are given. In particular, a law relating the second-harmonic progression with the density of bubbles is found. The propagation of plane pulses is also analyzed to give results on nonlinear attenuation, changes of frequency, and self-demodulation. The influence of the resonance frequency of bubbles on the nonlinear field is then determined. Differences and similarities with nonlinear acoustics in homogeneous fluid are shown and commented. The possibilities and limits of an equivalent nonlinear fluid are then discussed. The propagation of a high-frequency pulsed signal in a bubbly liquid used in a biological application is also the subject of numerical experiments, for frequencies near and beyond the resonance frequency of the bubbles.

Nonlinear ultrasonic propagation in bubbly liquids: a numerical model

Nonlinear ultrasonic waves in bubbly liquids with nonhomogeneous bubble distribution: Numerical experiments.

Christian Vanhille

Papers

Experimental and theoretical investigation of the mean acoustic pressure in the cavitation field.

On the physical origin of conical bubble structure under an ultrasonic horn.

Acoustic cavitation mechanism: A nonlinear model

Nonlinear ultrasonic propagation in bubbly liquids: a numerical model

Nonlinear ultrasonic waves in bubbly liquids with nonhomogeneous bubble distribution: Numerical experiments.