We present an experimental study on the drag reduction by polymers in Taylor–Couette turbulence at Reynolds numbers ( $Re$ ) ranging from $4\times 10^3$ to $2.5\times 10^4$ . In this regime, Taylor vortex is and accounts for more than 50 % of total angular velocity flux. Polyacrylamide with two different average molecular weights are used. It found that rate increases polymer concentration approaches maximum (MDR) limit. At MDR, friction factor follows $-0.58$ scaling, i.e. $C_f \sim...

A machine learning assisted algorithm was proposed to quickly obtain the inertial lift forces, allowing researchers expedite development of microfluidic devices for particle manipulation without computationally costly simulations.

Inertial migration has emerged as an efficient tool for manipulating both biological and engineered particles that commonly exist with non-spherical shapes in microfluidic devices. There have been numerous studies on the inertial of spherical particles, whereas are still largely unexplored. Here, we conduct three-dimensional direct numerical simulations to study rigid cylindrical rectangular microchannels different width/height ratios under channel Reynolds numbers (Re) varying from 50 400....

The presence of a dispersed phase can significantly modulate the drag in turbulent systems. We derived conserved quantity that characterizes radial transport azimuthal momentum fluid–fluid two-phase Taylor–Couette turbulence. This consists contributions from advection, diffusion and interface, which are closely related to density, viscosity interfacial tension, respectively. found interface-resolved direct numerical simulations interface consistently produces positive contribution leads...

In this study, we investigate the coupling effects of roughness and wall shear in an annular centrifugal Rayleigh-B\'enard convection (ACRBC) system, where two cylinders rotate with different angular velocities. Two-dimensional direct numerical simulations are conducted within a Rayleigh number range $10^{6} \leq Ra 10^{8}$, non-dimensional velocity difference ($\varOmega$), representing shear, varied from 0 to 1. The Prandtl is fixed at $Pr = 4.3$, inverse Rossby $Ro^{-1} 20$, radius ratio...

Turbulent emulsions are ubiquitous in chemical engineering, food processing, pharmaceuticals and other fields. However, our experimental understanding of this area remains limited due to the multiscale nature turbulent flow presence extensive interfaces, which pose significant challenges optical measurements. In study, we address these by precisely matching refractive indices continuous dispersed phases, enabling us measure local velocity information at high volume fractions. The emulsion is...

We investigate the coupling effects of two-phase interface, viscosity ratio and density dispersed phase to continuous on flow statistics in Taylor–Couette turbulence at a system Reynolds number $6\times 10^3$ Weber 10 using interface-resolved three-dimensional direct numerical simulations with volume-of-fluid method. Our study focuses four different scenarios: neutral droplets, low-viscosity light droplets droplets. find that primarily contribute drag enhancement through whereas reduce...

The presence of dispersed-phase droplets can result in a notable increase system's drag. However, our understanding the mechanism underlying this phenomenon remains limited. In study, we use three-dimensional direct numerical simulations with modified multi-marker volume-of-fluid method to investigate liquid–liquid two-phase turbulence Taylor–Couette geometry. dispersed phase has same density and viscosity as continuous phase. Reynolds number $Re\equiv r_i\omega _i d/\nu$ is fixed at 5200,...

Direct numerical simulations are performed to explore the effects of rotating direction vertically asymmetric rough wall on transport properties Taylor–Couette (TC) flow, up a Taylor number ${Ta} = 2.39\times 10^{7}$ . It is shown that, compared with smooth wall, vertical strips can enhance dimensionless torque ${Nu}_{\omega }$ More importantly, at high Ta , clockwise rotation inner (where fluid sheared by steeper slope side strips) results in significantly greater enhancement...

Although artificial micromotors with unconventional shapes are emerging as a powerful tool in various applications, little research has been undertaken to clarify their propulsion mechanism, especially how the shape effect alters bubble dynamics and hydrodynamic flows. In this study, we fabricated two types of bowl-shaped investigate distinct due concave convex surfaces, by coating platinum (Pt) layer on either surface or micromotor. single-bubble mode at low fuel concentration,...

Inertial migration has proven effective for high-throughput manipulation of tiny particles in confined flows. However, complex and even controversial relationships between hydrodynamic forces flow conditions hinder the development an explicit formula inertial lift acting on finite-sized at Reynolds numbers hundreds. Herein, we reveal different scaling laws shear gradient-induced wall-induced by separating contributions pressure stress viscous stress. A direct result this treatment is a new...

Controlled assembly of nanoparticles (NPs) has garnered much interest over the past two decades. Beyond established techniques, new methods utilizing local short-range or large-scale long-range interactions remain to be explored achieve diverse micro- and nanoscale structures. Here, we report controlled emergence vortex-pair arrays within monodispersed gold nanorods (AuNRs) by applying a direct current (dc) electric field across pair sawtooth electrodes. By employing in situ darkfield...

Abstract Controlled assembly of nanoparticles (NPs) has garnered much interest over the past two decades. Beyond established techniques, new methods utilizing local short‐range or large‐scale long‐range interactions remain to be explored achieve diverse micro‐ and nanoscale structures. Here, we report controlled emergence vortex‐pair arrays within monodispersed gold nanorods by applying a direct current electric field across pair sawtooth electrodes. By employing in situ darkfield microscopy...

We investigate the coupling effects of two-phase interface, viscosity ratio, and density ratio dispersed phase to continuous on flow statistics in Taylor-Couette turbulence at a system Reynolds number 6000 Weber 10 using interface-resolved three-dimensional direct numerical simulations with volume-of-fluid method. Our study focuses four different scenarios: neutral droplets, low-viscosity light droplets. find that droplets primarily contribute drag enhancement through while reduce system's...

The presence of dispersed-phase droplets can result in a notable increase the system's drag. However, our understanding mechanism underlying this phenomenon remains limited. In study, we use three-dimensional direct numerical simulations with modified multi-marker volume-of-fluid method to investigate liquid-liquid two-phase turbulence Taylor-Couette geometry. dispersed phase has same density and viscosity as continuous phase. Reynolds number $Re\equiv r_i\omega_i d/\nu$ is fixed at 5200,...

We present an experimental study on the drag reduction by polymers in Taylor-Couette turbulence at Reynolds numbers ($Re$) ranging from $4\times 10^3$ to $2.5\times 10^4$. In this $Re$ regime, Taylor vortex is and accounts for more than 50\% of total angular velocity flux. Polyacrylamide with two different average molecular weights are used. It found that rate increases polymer concentration approaches maximum (MDR) limit. At MDR, friction factor follows $-0.58$ scaling, i.e., $C_f \sim...

Nowadays, the requirement to preserve user privacy has avoided preservation of data that could be used correlate library non data.This paper mining and detection identify academic use patterns judge whether students' number published papers correlated use.All libraries datasets this were uploaded into a warehouse, allowing them managed, supervised analyzed.The showed by department, book from 2000 2015 15 years statistics between use.The technique is demonstrated using collected at Hohai...

The presence of a dispersed phase can significantly modulate the drag in turbulent systems. We derived conserved quantity that characterizes radial transport azimuthal momentum fluid-fluid two-phase Taylor-Couette turbulence. This consists contributions from advection, diffusion, and interface, which are closely related to density, viscosity, interfacial tension, respectively. found interface consistently produces positive contribution leads enhancement, while decreasing density viscosity...

Direct numerical simulations are performed to explore the effects of rotating direction vertical asymmetric rough wall on transport properties Taylor-Couette (TC) flow up a Taylor number $\textit{Ta} = 2.39 \times 10^7$. It is shown that compared smooth wall, with strips can enhance dimensionless torque \textit{Nu}$_\omega$, and more importantly, at high \textit{Ta} clockwise rotation inner (the fluid sheared by steeper slope side strips) results in significantly bigger enhancement as...