Secondary flow's role in the overall frictional behaviour is circumscribed during this period of change. Achieving efficient mixing at a low drag and a low, yet non-zero, Reynolds number is expected to be a topic of great interest. Part 2 of the Taylor-Couette and related flows theme issue is dedicated to this article; it also marks the centennial of Taylor's seminal Philosophical Transactions paper.
Noise is incorporated into numerical simulations and experiments on axisymmetric, wide-gap spherical Couette flow. Such explorations hold considerable importance because most naturally occurring flows are susceptible to random fluctuations. Fluctuations, random in their temporal occurrence and having a zero mean, are added to the inner sphere's rotation, resulting in noise entering the flow. Incompressible, viscous fluid movement results from either the rotation of the inner sphere alone, or from the simultaneous rotation of both spheres. Under the influence of additive noise, mean flow generation was observed. In particular conditions, the relative amplification of meridional kinetic energy surpassed that of the azimuthal component. The calculated flow velocities were confirmed by measurements taken using a laser Doppler anemometer. To illuminate the rapid enhancement of meridional kinetic energy in flows generated by changes in the spheres' co-rotation, a model is put forth. Analysis of the linear stability of flows resulting from the inner sphere's rotation indicated a decline in the critical Reynolds number, which correlated to the onset of the first instability. Near the critical Reynolds number, there was a demonstrable local minimum in the mean flow generation, a result compatible with available theoretical predictions. In this theme issue, specifically part 2, 'Taylor-Couette and related flows,' this article marks the centennial of Taylor's pioneering Philosophical Transactions paper.
Taylor-Couette flow, a subject of both experimental and theoretical astrophysical interest, is reviewed concisely. Despite the differential rotation of interest flows, with the inner cylinder spinning faster than the outer, the system remains linearly stable against Rayleigh's inviscid centrifugal instability. Hydrodynamic flows, exhibiting quasi-Keplerian characteristics, show nonlinear stability up to shear Reynolds numbers of [Formula see text], with any turbulence solely attributable to axial boundary interactions, not the radial shear itself. Cabozantinib In agreement, direct numerical simulations are still unable to model Reynolds numbers of such a high magnitude. Accretion disk turbulence, specifically that driven by radial shear, doesn't have a solely hydrodynamic origin. The theory postulates linear magnetohydrodynamic (MHD) instabilities, chief among them the standard magnetorotational instability (SMRI), present in astrophysical discs. SMRI research utilizing MHD Taylor-Couette experiments faces a significant hurdle in the form of liquid metals' low magnetic Prandtl numbers. High fluid Reynolds numbers are required, coupled with a fastidious management of axial boundaries. The ongoing efforts in the field of laboratory SMRI research have led to the identification of some intriguing non-inductive analogs of SMRI, and the successful implementation of SMRI utilizing conducting axial boundaries, as recently reported. Important unanswered astrophysical questions and potential near-term developments are explored, especially regarding their interactions. The 'Taylor-Couette and related flows' theme issue, comprising part 2, which commemorates the centennial of Taylor's Philosophical Transactions paper, includes this article.
Using both experimental and numerical techniques, this study from a chemical engineering perspective, delved into the thermo-fluid dynamics of Taylor-Couette flow influenced by an axial temperature gradient. An experimental Taylor-Couette apparatus was employed, characterized by a jacket that was divided vertically into two halves. Utilizing flow visualization and temperature measurements for glycerol aqueous solutions of variable concentrations, six flow patterns were categorized: Case I (heat convection dominant), Case II (alternating heat convection and Taylor vortex flow), Case III (Taylor vortex dominant), Case IV (fluctuation-maintained Taylor cell structure), Case V (segregation of Couette and Taylor vortex flow), and Case VI (upward motion). A mapping of these flow modes was performed with respect to the Reynolds and Grashof numbers. Cases II, IV, V, and VI exhibit transitionary flow patterns from Case I to Case III, contingent upon the concentration. Heat convection, when applied to the Taylor-Couette flow in Case II, led to an improved heat transfer, as revealed by numerical simulations. Additionally, the average Nusselt number exhibited a higher value under the alternative flow regime compared to the stable Taylor vortex flow. Therefore, the mutual effect of heat convection and Taylor-Couette flow acts as a strong catalyst for improving heat transfer. This contribution is part of the 'Taylor-Couette and related flows' centennial theme, part 2 of a special issue, acknowledging the one-hundred-year mark of Taylor's Philosophical Transactions paper.
Our direct numerical simulations examine the Taylor-Couette flow of a dilute polymer solution, focusing on cases where solely the inner cylinder spins in a system exhibiting moderate curvature, which is further described by [Formula see text]. Employing the finitely extensible nonlinear elastic-Peterlin closure, a model of polymer dynamics is constructed. Simulations indicate a novel elasto-inertial rotating wave, with arrow-shaped features within the polymer stretch field, aligning perfectly with the streamwise axis. Cabozantinib A comprehensive analysis of the rotating wave pattern is presented, including its dependence on the dimensionless Reynolds and Weissenberg numbers. Arrow-shaped structures coexisting with diverse structural forms in flow states were identified in this study for the first time and are briefly analyzed. This article is part of a special thematic issue on Taylor-Couette and related flows, observing the centennial of Taylor's seminal Philosophical Transactions paper, focusing on the second part of the publication.
G. I. Taylor's seminal research paper, published in the Philosophical Transactions in 1923, focused on the stability of what we now identify as Taylor-Couette flow. Taylor's seminal linear stability analysis of fluid flow between rotating cylinders, published a century ago, has profoundly shaped the field of fluid mechanics. The paper's influence spans general rotating flows, geophysical flows, and astrophysical flows, notably for its role in the established acceptance of several foundational principles in fluid mechanics. A comprehensive two-part examination, this collection encompasses review and research articles, touching upon a wide array of current research areas, all fundamentally anchored in Taylor's seminal paper. Part 2 of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper' contains this article.
The profound impact of G. I. Taylor's 1923 study on Taylor-Couette flow instabilities has been instrumental in shaping subsequent research, thereby establishing a bedrock for the characterization of complex fluid systems needing precisely regulated hydrodynamics. A radial fluid injection method coupled with a TC flow system is employed in this study to examine the mixing characteristics of complex oil-in-water emulsions. The flow field within the annulus between the rotating inner and outer cylinders witnesses the radial injection and subsequent dispersion of a concentrated emulsion simulating oily bilgewater. An investigation into the resultant mixing dynamics is carried out, and effective intermixing coefficients are ascertained via the quantified variation in light reflection intensity from emulsion droplets in fresh and saltwater solutions. Changes in droplet size distribution (DSD) track the effects of the flow field and mixing conditions on emulsion stability, and the use of emulsified droplets as tracer particles is discussed in relation to changes in the dispersive Peclet, capillary, and Weber numbers. Larger droplet formation in oily wastewater systems correlates with improved separation during water treatment, and the observed droplet size distribution is found to be adjustable with variations in salt concentration, observation duration, and mixing conditions within the treatment chamber. In recognition of the centenary of Taylor's foundational Philosophical Transactions paper, this article is included in the 'Taylor-Couette and related flows' theme issue, part 2.
The International Classification for Functioning, Disability and Health (ICF) serves as the foundation for a new tinnitus inventory (ICF-TINI), detailed in this study, that measures the impact of tinnitus on an individual's function, activities, and societal engagement. And, subjects.
A cross-sectional study leveraged the ICF-TINI, a tool comprising 15 items stemming from the body function and activity components of the ICF framework. Chronic tinnitus affected 137 participants in our study. The two-structure framework's validity concerning body function, activities, and participation was established using confirmatory factor analysis. The suggested fit criteria were used to evaluate the model's fit, considering the chi-square (df), root mean square error of approximation, comparative fit index, incremental fit index, and Tucker-Lewis index values. Cabozantinib Internal consistency reliability was evaluated using Cronbach's alpha.
The ICF-TINI's presence of two structures was validated by fit indices, with factor loading values further establishing each item's satisfactory fit. The ICF's internal TINI consistently performed, showcasing a high level of reliability, measured at 0.93.
The impact of tinnitus on a person's physical well-being, daily routines, and social integration is evaluated with the reliable and valid ICFTINI instrument.