Home About us Contact
|
Home About us Contact | ||
|
|
||
Radius Ratio (radius + ratio)
Selected AbstractsDimer-Based Three-Dimensional Photonic CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Ian D. Hosein Abstract The self-assembly of polystyrene dimer- and spherocylinder-shaped colloids is achieved via controlled drying on glass and silicon substrates. 3D monoclinic colloidal crystal structures are determined from scanning electron microscopy images of sections prepared using focused ion-beam (FIB) milling. Full photonic bandgaps between the eighth and ninth bands are found for a systematic range of colloidal dimer shapes explored with respect to the degree of constituent lobe fusion and radius ratio. The pseudogap between bands 2 and 3 for spherocylinder-based monoclinic crystals is also probed using normal incidence reflection spectroscopy. [source] Characterization of Taylor vortex flow in a short liquid columnAICHE JOURNAL, Issue 12 2009Rensheng Deng Abstract We present a study on Taylor vortex flow in the annulus between a rotating inner cylinder and a stationary outer cylinder, featured with a wide gap (radius ratio is 0.613) and a short column (aspect ratio is 5.17). A particle image velocimetry (PIV) system was used to determine the position, shape, and velocity distribution of the vortices, by which the flow was also confirmed to lie in the nonwavy Taylor vortex regime for all operating conditions explored in this study. Our results suggest that end boundary effects are important, in which the vortex number decreases with decreasing column length. For a system with an aspect ratio of 5.17, six vortices appear in the gap with their position, size, and shape varying at different Reynolds numbers. The fluid velocities show an asymmetric feature with respect to the vortex centers, while the maximum axial and radial velocities increase almost linearly with the increasing reduced Reynolds number (Re , Rec). In addition, computational fluid dynamics study was employed under the same conditions, and its results agree well with the PIV measurements. Overall, this study provides a quantitative understanding of the formation of Taylor vortices in a constrained space. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Studying the Squeeze Forces and Tilting Moments in Misaligned Radial Face Seals ConingCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 3 2006G. M. Abdel-Rahman Abstract The Reynolds equation for misaligned radial face seals coning is solved numerically, and the squeeze effects on the separating forces and tilting moments are studied. Also, the variations in the seal characteristics with eccentricity, thin film thickness and radius ratio are presented. The numerical results for the forces and moments are given in nondimensional form. [source] Transition from vortex to wall driven turbulence production in the Taylor,Couette system with a rotating inner cylinderINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2002W. M. J. Batten Abstract Axisymmetrically stable turbulent Taylor vortices between two concentric cylinders are studied with respect to the transition from vortex to wall driven turbulent production. The outer cylinder is stationary and the inner cylinder rotates. A low Reynolds number turbulence model using the k - , formulation, facilitates an analysis of the velocity gradients in the Taylor,Couette flow. For a fixed inner radius, three radius ratios 0.734, 0.941 and 0.985 are employed to identify the Reynolds number range at which this transition occurs. At relatively low Reynolds numbers, turbulent production is shown to be dominated by the outflowing boundary of the Taylor vortex. As the Reynolds number increases, shear driven turbulence (due to the rotating cylinder) becomes the dominating factor. For relatively small gaps turbulent flow is shown to occur at Taylor numbers lower than previously reported. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||