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Full-Text Articles in Physics
Mixture Segregation Within Sonoluminescence Bubbles, Brian D. Storey, Andrew J. Szeri
Mixture Segregation Within Sonoluminescence Bubbles, Brian D. Storey, Andrew J. Szeri
Brian Storey
This paper concerns a relaxation of the assumption of uniform mixture composition in the interior of sonoluminescence bubbles. Intense temperature and pressure gradients within the bubble drive relative mass diffusion which overwhelms diffusion driven by concentration gradients. This thermal and pressure diffusion results in a robust compositional inhomogeneity in the bubble which lasts several orders of magnitude longer than the temperature peak or light pulse at the main collapse of the bubble. This effect has important consequences for control of sonoluminescence, gas dynamics, sonochemistry, and the physics of light production.
Nonextensive Statistical Mechanics For Rotating Quasi-Two-Dimensional Turbulence, Sunghwan Jung, Brian Storey, Julien Aubert, Harry Swinney
Nonextensive Statistical Mechanics For Rotating Quasi-Two-Dimensional Turbulence, Sunghwan Jung, Brian Storey, Julien Aubert, Harry Swinney
Brian Storey
We have conducted experiments on an asymmetrically forced quasi-two-dimensional turbulent flow in a rapidly rotating annulus. Assuming conservation of potential enstrophy and energy, we maximize a nonextensive entropy function to obtain the azimuthally averaged vorticity as a function of radial position. The predicted vorticity profile is in good accord with the observations. A nonextensive formalism is appropriate because long-range correlations between small-scale vortices give rise to large coherent structures in the turbulence. We also derive probability distribution functions for the vorticity from both extensive and nonextensive entropies, and we find that the prediction from nonextensive theory is in better accord …
Viscosity Measurements On Colloidal Dispersions (Nanofluids) For Heat Transfer Applications, Jessica Townsend, Rebecca J. Christianson, D Venerus, J Buongiorno, M A. Kedzierski, Et Al.
Viscosity Measurements On Colloidal Dispersions (Nanofluids) For Heat Transfer Applications, Jessica Townsend, Rebecca J. Christianson, D Venerus, J Buongiorno, M A. Kedzierski, Et Al.
Rebecca J. Christianson
This article reports viscosity data on a series of colloidal dispersions collected as part of the International Nanofluid Property Benchmark Exercise (INPBE). Data are reported for seven different fluids that include dispersions of metal-oxide nanoparticles in water, and in synthetic oil. These fluids, which are also referred to as nanofluids, are currently being researched for their potential to function as heat transfer fluids. In a recently published paper from the INPBE study, thermal conductivity data from more than 30 laboratories around the world were reported and analyzed. Here, we examine the influence of particle shape and concentration on the viscosity …
Nanofluid Properties And Their Effects On Convective Heat Transfer In An Electronics Cooling Application, Jessica Townsend, Rebecca Christianson
Nanofluid Properties And Their Effects On Convective Heat Transfer In An Electronics Cooling Application, Jessica Townsend, Rebecca Christianson
Rebecca J. Christianson
In the search for new, more effective coolant fluids, nanoparticle suspensions have shown promise due to their enhanced thermal conductivity. However, there is a concomitant increase in the viscosity, requiring an increase in pumping power to achieve the same flow rate.Studies of flow cooling in simple geometries indicate that there is a benefit to using nanofluids, but it is difficult to justify extending these results to the far more complicated geometries. Moreover, with the variability of property measurements found in literature, it is possible to show conflicting results from the same set of flow-cooling data. In this work we present …
Viscosity Measurements On Colloidal Dispersions (Nanofluids) For Heat Transfer Applications, Jessica Townsend, Rebecca J. Christianson, D Venerus, J Buongiorno, M A. Kedzierski, Et Al.
Viscosity Measurements On Colloidal Dispersions (Nanofluids) For Heat Transfer Applications, Jessica Townsend, Rebecca J. Christianson, D Venerus, J Buongiorno, M A. Kedzierski, Et Al.
Jessica Townsend
This article reports viscosity data on a series of colloidal dispersions collected as part of the International Nanofluid Property Benchmark Exercise (INPBE). Data are reported for seven different fluids that include dispersions of metal-oxide nanoparticles in water, and in synthetic oil. These fluids, which are also referred to as nanofluids, are currently being researched for their potential to function as heat transfer fluids. In a recently published paper from the INPBE study, thermal conductivity data from more than 30 laboratories around the world were reported and analyzed. Here, we examine the influence of particle shape and concentration on the viscosity …
Nanofluid Properties And Their Effects On Convective Heat Transfer In An Electronics Cooling Application, Jessica Townsend, Rebecca Christianson
Nanofluid Properties And Their Effects On Convective Heat Transfer In An Electronics Cooling Application, Jessica Townsend, Rebecca Christianson
Jessica Townsend
In the search for new, more effective coolant fluids, nanoparticle suspensions have shown promise due to their enhanced thermal conductivity. However, there is a concomitant increase in the viscosity, requiring an increase in pumping power to achieve the same flow rate.Studies of flow cooling in simple geometries indicate that there is a benefit to using nanofluids, but it is difficult to justify extending these results to the far more complicated geometries. Moreover, with the variability of property measurements found in literature, it is possible to show conflicting results from the same set of flow-cooling data. In this work we present …
A Depth-Averaged Electrokinetic Flow Model For Shallow Microchannels, Hao Lin, Brian D. Storey, Juan G. Santiago
A Depth-Averaged Electrokinetic Flow Model For Shallow Microchannels, Hao Lin, Brian D. Storey, Juan G. Santiago
Brian Storey
Electrokinetic flows with heterogeneous conductivity configuration occur widely in microfluidic applications such as sample stacking and multidimensional assays. Electromechanical coupling in these flows may lead to complex flow phenomena, such as sample dispersion due to electro-osmotic velocity mismatch, and electrokinetic instability (EKI). In this work we develop a generalized electrokinetic model suitable for the study of microchannel flows with conductivity gradients and shallow-channel geometry. An asymptotic analysis is performed with the channel depth-to-width ratio as a smallness parameter, and the three-dimensional equations are reduced to a set of depth-averaged equations governing in-plane flow dynamics. The momentum equation uses a Darcy–Brinkman–Forchheimer-type …