Dynamics of Microbubbles Oscillating in Rheopectic Fluids Subject to Acoustic Pressure Field

IF 1.3 4区工程技术 Q4 MECHANICS

Journal of Applied Fluid Mechanics Pub Date : 2023-10-01 DOI:10.47176/jafm.16.10.1882

A. Abdollahi, A. Rafiei, M. Ahmadi, M. Pourjafar-Chelikdani, K. Sadeghy

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引用次数: 0

Abstract

In the present work, the dynamics of a single spherical gas bubble surrounded by a rheopectic fluid obeying the Quemada model is numerically investigated while the bubble undergoes oscillatory motion due to acoustic forcing. The generalized form of the Rayleigh–Plesset equation has been used for studying bubble dynamics in Quemada fluids. The integro-differential equation representing the dynamics of the bubble is solved numerically using the finite-element method (FEM) and also the Gauss–Laguerre quadrature (GLQ) method. The effect of rheopexy number (Rx) and viscosity ratio (ξ) are then investigated over a wide range of working parameters. Numerical results show that the rheopectic behavior of the fluid surrounding the bubble can dramatically affect the bubble dynamics. It is predicted that for highly anti-thixotropic fluids, harmonics are affected so much so that the bubble may exhibit chaotic behavior. For instance, at Rx = 0.001 and ξ = 1/81, a one-micron-sized bubble may attain a size almost 30 times of its initial size. The general conclusion is that, in sonography, microbubbles dispersed in rheopectic fluids may indeed be considered as a potent ultrasound contrast agent provided that the fluid is just moderately anti-thixotropic otherwise its chaotic response might damage the adjacent tissues.

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声压场作用下流变流体中微泡振荡动力学研究

在本工作中，数值研究了一个由服从Quemada模型的流变流体包围的单个球形气泡在声强迫下进行振荡运动时的动力学。Rayleigh-Plesset方程的广义形式已被用于研究Quemada流体中的气泡动力学。采用有限元法(FEM)和高斯-拉盖尔正交法(GLQ)对表征气泡动力学的积分-微分方程进行了数值求解。然后在广泛的工作参数范围内研究了流变分数(Rx)和粘度比(ξ)的影响。数值结果表明，气泡周围流体的流变特性对气泡动力学有显著影响。预测对于高度抗触变的流体，谐波受到很大的影响，气泡可能表现出混沌行为。例如，当Rx = 0.001和ξ = 1/81时，一个1微米大小的气泡可能达到其初始尺寸的近30倍。总的结论是，在超声检查中，分散在流变液中的微泡确实可以被认为是一种有效的超声造影剂，前提是流体只是适度的抗触变性，否则其混沌反应可能会损害邻近组织。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Applied Fluid Mechanics THERMODYNAMICS-MECHANICS

CiteScore

2.00

自引率

20.00%

发文量

138

审稿时长

>12 weeks

期刊介绍： The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating. The motivation for this new fluid mechanics journal is driven by the following points: (1) there is a need to have an e-journal accessible to all fluid mechanics researchers, (2) scientists from third- world countries need a venue that does not incur publication costs, (3) quality papers deserve rapid and fast publication through an efficient peer review process, and (4) an outlet is needed for rapid dissemination of fluid mechanics conferences held in Asian countries. Pertaining to this latter point, there presently exist some excellent conferences devoted to the promotion of fluid mechanics in the region such as the Asian Congress of Fluid Mechanics which began in 1980 and nominally takes place in one of the Asian countries every two years. We hope that the proposed journal provides and additional impetus for promoting applied fluids research and associated activities in this continent. The journal is under the umbrella of the Physics Society of Iran with the collaboration of Isfahan University of Technology (IUT) .