Showing papers by "Dhiman Chatterjee published in 2008"
01 Sep 2008
TL;DR: In this paper, a numerical study of turbulent flow over the S-shaped hydrofoil at 0° angle of attack has been reported, where the flow takes place over concave and convex surfaces and is accompanied by the favorable and adverse pressure gradients and flow separation.
Abstract: In this paper, a numerical study of turbulent flow over the S-shaped hydrofoil at 0° angle of attack has been reported. Here, the flow takes place over concave and convex surfaces and is accompanied by the favourable and adverse pressure gradients and flow separation. Modelling such a flow poses a formidable challenge. In the present work four turbulence models, namely, k–∊ realizable, k–ω shear stress transport
13 citations
14 Jul 2008
TL;DR: In this paper, an interfacial rheology model for the encapsulation of microbubbles was developed to measure attenuation and scattering of ultrasound through solution of commercial contrast agents such as Optison (GE Health Care, Princeton, NJ) and Definity (Bristol Meyer Squibb Imaging, North Ballerina, MA).
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 Optison (GE Health Care, Princeton, NJ) and Definity (Bristol Meyer‐Squibb Imaging, North Ballerina, MA). We have developed an interfacial rheology model for the encapsulation of such microbubbles. By matching with experimental data, we obtain the characteristic rheological parameters. We compare model predictions with other experiments. We also investigate microbubble destruction under acoustic excitation by measuring time‐varying attenuation data. Three regions of acoustic pressure amplitudes are found: at low pressure, there is no destruction; at slightly higher pressure bubbles are destroyed, and the rate of destruction depends on a combination of PRF and amplitude. At a still higher pressure amplitude, the ...