Showing papers by "Dhiman Chatterjee published in 2006"
TL;DR: In this article, the authors analyzed the dynamics of a single bubble in a time-varying pressure field, for parameter ranges representative of those experimental conditions, using the method of multiple scales (MMS).
Abstract: In recent experimental work, Chatterjee and Arakeri have demonstrated that an imposed acoustic field of sufficiently high strength and frequency can suppress or control cavitation. In this paper, we analytically study the equation governing the dynamics of a single bubble in a time-varying pressure field, for parameter ranges representative of those experimental conditions. The governing equation is strongly nonlinear and intractable in general; however, for the parameter ranges of interest, we are able to nondimensionalize and scale the governing equation into a form that, though still strongly nonlinear, is amenable to analysis using the method of multiple scales (MMS) based on an arbitrarily chosen “small” parameter ∊. Removal of secular terms, a key step in the MMS, raises an interesting issue which we discuss. Second order MMS gives the slow average evolution of the bubble radius. Numerical solutions of the original equation match the MMS approximation well on time scales of \(\cal O\)(1/∊). The MMS approximation also provides insight into the roles played by relevant physical parameters in the system. Our results provide theoretical support for the abovementioned experimental results.
7 citations
12 Jun 2006
TL;DR: In this paper, the authors measured attenuation and scattering of ultrasound through solution of commercial contrast agents such as Sonazoid and Definity, and compared model predictions with measured subharmonic responses.
Abstract: Intravenously injected encapsulated microbubbles improve the contrast of an ultrasound image. Their destruction is used in measuring blood flow, stimulating arteriogenesis, and drug delivery. We measure attenuation and scattering of ultrasound through solution of commercial contrast agents such as Sonazoid and Definity. We have developed a number of different interfacial rheology models for the encapsulation of such microbubbles. By matching with experimentally measured attenuation, we obtain the characteristic rheological parameters. We compare model predictions with measured subharmonic responses. We also investigate microbubble destruction under acoustic excitation by measuring time‐varying attenuation data.