This research focuses on the observed flow regimes in Taylor-Couette flow, utilizing a radius ratio of [Formula see text], and spanning various Reynolds numbers up to [Formula see text]. A visualization approach is used to examine the dynamics of the flow. Within the context of centrifugally unstable flow, the research explores the flow states associated with counter-rotating cylinders and situations involving only inner cylinder rotation. Not only Taylor-vortex and wavy-vortex flows, but a variety of new flow configurations are apparent within the cylindrical annulus, especially during the transition to turbulence. The system's interior demonstrates the coexistence of turbulent and laminar regions. An irregular Taylor-vortex flow, turbulent spots, turbulent bursts, and non-stationary turbulent vortices were all present in the observation. One prominent characteristic is a single, axially aligned vortex positioned between the inner and outer cylinder. A flow-regime diagram illustrates the various flow regimes occurring when cylinders rotate independently of each other. The 'Taylor-Couette and related flows' theme issue, part 2, features this article, commemorating the centennial of Taylor's landmark Philosophical Transactions paper.

Elasto-inertial turbulence (EIT) dynamic properties are examined within a Taylor-Couette configuration. Non-negligible inertia and viscoelasticity are foundational to the development of EIT's chaotic flow state. Direct flow visualization, alongside torque measurements, serves to confirm the earlier emergence of EIT, as contrasted with purely inertial instabilities (and the phenomena of inertial turbulence). Herein, for the first time, we delve into the scaling of the pseudo-Nusselt number, considering its dependence on inertia and elasticity. EIT's intermediate behavior, preceding its fully developed chaotic state, is demonstrably characterized by fluctuations in the friction coefficient, temporal frequency spectra, and spatial power density spectra; both high inertia and elasticity are crucial in this transition. Throughout this transitional phase, the impact of secondary flows on the broader frictional mechanics is constrained. The attainment of efficient mixing, characterized by low drag and a low, yet non-zero, Reynolds number, is anticipated to hold substantial interest. The theme issue on Taylor-Couette and related flows, in its second part, includes this article, commemorating the centennial of Taylor's Philosophical Transactions paper.

The presence of noise is considered in numerical simulations and experiments of the axisymmetric spherical Couette flow, characterized by a wide gap. These studies are essential given that the majority of natural processes are prone to random fluctuations in their flow. Random, zero-mean fluctuations in the timing of the inner sphere's rotation contribute to noise within the flow. Flows of viscous, incompressible fluids are a result of either the rotation of only the interior sphere, or of both spheres rotating together. It was found that mean flow generation resulted from the introduction of additive noise. A comparative analysis indicated a higher relative amplification of meridional kinetic energy, under specific conditions, as opposed to the azimuthal component. Laser Doppler anemometer readings were used to verify the calculated flow velocities. To understand the rapid rise of meridional kinetic energy in the flows created by changing the co-rotation of the spheres, a model is introduced. Our linear stability analysis, applied to flows originating from the rotation of the inner sphere, exhibited a decrease in the critical Reynolds number, indicative of the commencement of the initial instability. Observing the mean flow generation, a local minimum emerged as the Reynolds number approached the critical threshold, thus corroborating theoretical projections. Celebrating the centennial of Taylor's seminal Philosophical Transactions paper, this article is part of the 'Taylor-Couette and related flows' theme issue's second section.

The astrophysical motivations behind experimental and theoretical studies of Taylor-Couette flow are highlighted in a concise review. Namodenoson research buy Interest flow rotation rates vary differentially, with the inner cylinder rotating more quickly than the outer, resulting in linear stability against Rayleigh's inviscid centrifugal instability. Quasi-Keplerian hydrodynamic flows remain nonlinearly stable, even at shear Reynolds numbers as high as [Formula see text]; any observable turbulence originates from interactions with the axial boundaries, not the radial shear. Direct numerical simulations, though in agreement, are currently limited in their capacity to reach these exceptionally high Reynolds numbers. Accretion disk turbulence, specifically that driven by radial shear, doesn't have a solely hydrodynamic origin. Within astrophysical discs, theory anticipates linear magnetohydrodynamic (MHD) instabilities, the standard magnetorotational instability (SMRI) being a key example. SMRI-oriented MHD Taylor-Couette experiments encounter difficulties due to the low magnetic Prandtl numbers inherent in liquid metals. For optimal performance, axial boundaries require careful control, alongside high fluid Reynolds numbers. Laboratory SMRI research has borne fruit, yielding the discovery of unique, non-inductive counterparts of SMRI and the recent proof of concept for implementing SMRI with conducting axial boundaries. Important unanswered astrophysical questions and potential near-term developments are explored, especially regarding their interactions. Part 2 of the theme issue, 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper', contains this article.

From the perspective of chemical engineering, this study undertook a combined numerical and experimental investigation of the thermo-fluid dynamics of Taylor-Couette flow, considering an axial temperature gradient. Utilizing a Taylor-Couette apparatus, the experiments involved a jacket that was separated vertically into two compartments. Flow visualization and temperature measurement data for glycerol aqueous solutions at different concentrations enabled the categorization of flow patterns into six distinct modes, including Case I (heat convection dominant), Case II (alternating heat convection and Taylor vortex flow), Case III (Taylor vortex dominant), Case IV (fluctuating Taylor cell structure), Case V (segregation between Couette and Taylor vortex flows), and Case VI (upward motion). immunity cytokine These flow modes were depicted in terms of the Reynolds and Grashof numbers' values. The flow patterns of Cases II, IV, V, and VI mediate the shift between Case I and Case III, fluctuating with concentration. Furthermore, numerical simulations indicated that, in Case II, the introduction of heat convection into the Taylor-Couette flow resulted in enhanced heat transfer. The alternate flow resulted in a higher average Nusselt number than the stable Taylor vortex flow. In this regard, the interplay between heat convection and Taylor-Couette flow represents a significant strategy for augmenting heat transfer. Part 2 of the theme issue, dedicated to Taylor-Couette and related flows, includes this article, celebrating the centennial of Taylor's important Philosophical Transactions paper.

Direct numerical simulations of the Taylor-Couette flow are presented for a dilute polymer solution under the condition of inner cylinder rotation and a moderate system curvature, as indicated in [Formula see text]. Employing the finitely extensible nonlinear elastic-Peterlin closure, a model of polymer dynamics is constructed. Simulations uncovered a novel elasto-inertial rotating wave, featuring polymer stretch field structures shaped like arrows, oriented parallel to the streamwise direction. A comprehensive analysis of the rotating wave pattern is presented, including its dependence on the dimensionless Reynolds and Weissenberg numbers. This research has newly discovered flow states possessing arrow-shaped structures, alongside other kinds of structures, and offers a succinct examination of these. Part 2 of the special issue on Taylor-Couette and related flows, in celebration of the centennial of Taylor's original Philosophical Transactions article, includes this article.

Taylor's seminal 1923 paper, published in the Philosophical Transactions, explored the stability characteristics of the flow configuration now called Taylor-Couette flow. In the century since its publication, Taylor's groundbreaking linear stability analysis of fluid flow between rotating cylinders has been crucial in advancing the field of fluid mechanics. The influence of the paper has reached across general rotational flows, geophysical currents, and astrophysical movements, showcasing its crucial role in solidifying fundamental fluid mechanics concepts now widely recognized. This two-part publication features a compilation of review and research articles, exploring an extensive spectrum of contemporary research topics, all deeply rooted in Taylor's landmark paper. This article forms part of the themed section 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (Part 2)'

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. Radial injection of concentrated emulsion, designed to mimic oily bilgewater, occurs within the annulus formed by the rotating inner and outer cylinders, leading to dispersion within the flow field. Laboratory Automation Software We evaluate the resultant mixing dynamics, and precisely calculate the effective intermixing coefficients via the observed alteration in light reflection intensity from emulsion droplets situated within fresh and saline water. Changes in emulsion stability, resulting from variations in flow field and mixing conditions, are recorded through droplet size distribution (DSD) measurements; additionally, the use of emulsified droplets as tracer particles is examined in light of changes in dispersive Peclet, capillary, and Weber numbers.