Investigation on drag reduction on rotating blade surfaces with microtextures

• Qinsong Zhu,
• Chen Zhang,
• Fuhang Yu and
• Yan Xu

Beilstein J. Nanotechnol. 2024, 15, 833–853, doi:10.3762/bjnano.15.70

• microstructures on the shark skin surface to study the effects on hydrodynamics and aerodynamics. Within these extremely small structures, a low-speed, stable fluid flow exists, which can mitigate turbulences and enhance the stability of fluid motion within the boundary layer, resulting in a reduction of

• stress, and ρ is the density. where δ is the thickness of the boundary layer. The flow condition around the flat plate wall can be determined by the dimensionless local Reynolds number. where x is the distance from the inlet along the fluid flow direction. For Rex < 3 × 105, the flow in the boundary

Functional fibrillar interfaces: Biological hair as inspiration across scales

• Guillermo J. Amador,
• Brett Klaassen van Oorschot,
• Caiying Liao,
• Jianing Wu and
• Da Wei

Beilstein J. Nanotechnol. 2024, 15, 664–677, doi:10.3762/bjnano.15.55

• honey bees have been found to facilitate both the collection and removal of pollen grains through the geometries of the hair arrays on their eyes and grooming appendages [44]. Mammalian fur effectively sheds contaminants because the hair deflects when exposed to a fluid flow. This deflection generates a

• closed. The captured organic matter in the fans is consumed by sweeping the mandibles over the closed fans [120]. Choanoflagellates are unicellular organisms that use filter feeding. They drive fluid flow through a conical filter consisting of microvilli with diameters of 100–200 nm, spaced 200–700 nm

• apart [121][122]. While the microvilli contain actin and myosin, which together enable motility during escapes and help to transport trapped organic matter for consumption [123], they function passively when filtering organic matter. The structure driving the fluid flow through the filter remains

Application of nanoarchitectonics in moist-electric generation

• Jia-Cheng Feng and
• Hong Xia

Beilstein J. Nanotechnol. 2022, 13, 1185–1200, doi:10.3762/bjnano.13.99

• . Top: A pressure-driven flow carries the net ionic charge within the double layer, generating a streaming current. Bottom: A potential gradient generates both an electro-osmotic fluid flow (black arrows) and an additional electrophoretic ion velocity (colored arrows). Figure 1g was reprinted with

A review on slip boundary conditions at the nanoscale: recent development and applications

• Ruifei Wang,
• Jin Chai,
• Bobo Luo,
• Xiong Liu,
• Jianting Zhang,
• Min Wu,
• Mingdan Wei and
• Zhuanyue Ma

Beilstein J. Nanotechnol. 2021, 12, 1237–1251, doi:10.3762/bjnano.12.91

• applications of nanofluidics with tunable slip length are discussed. Finally, the conclusions are drawn and possible future directions about slip boundary conditions for nanoscale fluid flow are prospected. Review 1 Background 1.1 Definition of slip length and its microscopic expression As illustrated in

• by many studies that if the amplitude is comparable to or smaller than the local slip length, then an increase in amplitude leads to a reduction of the effective slip length [86][87]. Among those studies, MD simulations conducted by Yang show that compared with the fluid flow at smooth hydrophobic

• investigations focused on the derivation of the prediction bounds for the effective slip length in some targeted cases [49][82]. For example, it has been demonstrated that the Hashin–Shtrikman upper and lower bounds can be applied to the effective slip length for a fluid flow on arbitrary two-component textures

An overview of microneedle applications, materials, and fabrication methods

• Zahra Faraji Rad,
• Philip D. Prewett and
• Graham J. Davies

Beilstein J. Nanotechnol. 2021, 12, 1034–1046, doi:10.3762/bjnano.12.77

• or height, and shaft and tip shape. Other parameters including fluid flow rates, biocompatibility, penetration force, fragility, relative simplicity, and cost of fabrication are all key design considerations. The final design will depend on the limitations of the fabrication method and the mechanical

• direction through the skin. Embedding open-side channels on microneedle shafts is a novel approach, providing a passage through the skin for fluid flow and the manufacture is far easier than that for lumens in hollow microneedles. Despite decades of research and small incremental advances in manufacturing

Magnetohydrodynamic stagnation point on a Casson nanofluid flow over a radially stretching sheet

• Ganji Narender,
• Kamatam Govardhan and
• Gobburu Sreedhar Sarma

Beilstein J. Nanotechnol. 2020, 11, 1303–1315, doi:10.3762/bjnano.11.114

• the surface of the fluid flow. The Brownian motion and thermophoretic effects have been considered as well as the convective surface conditions. A convective heating process is applied to regulate the sheet temperature Tw. The nanoparticle concentration, Cw, is assumed to be constant. When y values

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• thermophoresis and fluid flow can be used to highly concentrate (trap) nanoparticles and molecules [24][25]. Suspended biological cells can be easily thermophoretically manipulated by harnessing the permittivity gradient in the electric double layer of the charged surface of the cell membrane [26]. Optical

Vibration analysis and pull-in instability behavior in a multiwalled piezoelectric nanosensor with fluid flow conveyance

• Sayyid H. Hashemi Kachapi

Beilstein J. Nanotechnol. 2020, 11, 1072–1081, doi:10.3762/bjnano.11.92

Effect of magnetic field, heat generation and absorption on nanofluid flow over a nonlinear stretching sheet

• Santoshi Misra and
• Govardhan Kamatam

Beilstein J. Nanotechnol. 2020, 11, 976–990, doi:10.3762/bjnano.11.82

• –corrector method is employed to solve the equations. The impact of the dimensionless parameters, including the Brownian motion, thermophoresis, magnetic field, heat generation and absorption parameters, on the velocity, temperature and nanoparticle concentration of fluid flow are analysed systematically

• . [4], studied the fluid flow using a semi-infinite flat surface with the heat generation and absorption coefficient. Anderson [5] conducted experiments on fluid flow using the finite difference method which seemed amenable to provide accurate results. The problem involving laminar flow due to

• slip conditions for the boundary layer flow to investigate the velocity, temperature and concentration changes with regard to various dimensionless parameters in the fluid flow under the influence of a magnetic field. Besthapu and Bandari [10] have analysed the heat and mass transfer rates using Casson

Understanding nanoparticle flow with a new in vitro experimental and computational approach using hydrogel channels

• Armel Boutchuen,
• Dell Zimmerman,
• Abdollah Arabshahi,
• John Melnyczuk and
• Soubantika Palchoudhury

Beilstein J. Nanotechnol. 2020, 11, 296–309, doi:10.3762/bjnano.11.22

• recorded in capillaries [45]. Blood flow within the tumor and liver are also slower. This induces a fluid flow pattern from the center outwards in these regions and the accumulation of micro- and nanoparticles on the walls of the vasculature [46] leading to a possible loss of NP drugs. Loss of the NP drug

• conditions for the geometry. The nanofluid entered the hydrogel channel with an average velocity of 0.0051 m·s−1 and 0.0054 m·s−1 for which the Reynolds numbers based on the diameter of the tube were 120.1 and 127.1, respectively. The fluid flow within the hydrogel channel was considered laminar and

• results are grid independent. The computed mass losses of the particles are 1.341% and 6.253% for 4.12 g and 2.008 g inlet concentrations of NP fluid flow in hydrogel channels, respectively. It is observed that the numerical simulation results favorably agree with experimental data (1.286% and 5.96

An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

• Weili Liu,
• Hongjian Ni,
• Peng Wang and
• Yi Zhou

Beilstein J. Nanotechnol. 2020, 11, 24–40, doi:10.3762/bjnano.11.3

• locomotion [13][22]. Thus, the triangular grooves seen in the nonsmooth structure of animal surfaces have become an effective means to reduce the viscous drag associated with fluid flow. Given the urgent demand to decrease pressure loss in fluid transport and the practicability of bionic theory, the grooved

• flow drag with the bionic pipeline under the same condition. Governing equations A commercial CFD tool, ANSYS Fluent-18.0, was used to calculate the turbulent flow in the pipe and the concentric annulus. Near-wall turbulence characteristics of a drag-reducing polymer fluid flow in the concentric

• can be seen in Figure 7c, the effect of the burrs was to increase the surface roughness of the pipeline. Besides, the greater the surface roughness was, the higher the pressure loss of fluid flow was. Therefore, in the experiment, the burrs on the pipeline surface caused pressure loss, which resulted

Effects of surface charge and boundary slip on time-periodic pressure-driven flow and electrokinetic energy conversion in a nanotube

• Mandula Buren,
• Yongjun Jian,
• Yingchun Zhao,
• Long Chang and
• Quansheng Liu

Beilstein J. Nanotechnol. 2019, 10, 1628–1635, doi:10.3762/bjnano.10.158

• , the continuum hydrodynamics for fluid flow is valid because the Debye length and the radius considered here are much larger than the mean free path of the liquid in the nanotube [31]. When the boundary surface of a nanochannel is molecularly smooth, the surface asperity barriers do not exist and

Preparation and morphology-dependent wettability of porous alumina membranes

• Dmitry L. Shimanovich,
• Alla I. Vorobjova,
• Daria I. Tishkevich,
• Alex V. Trukhanov,
• Maxim V. Zdorovets and
• Artem L. Kozlovskiy

Beilstein J. Nanotechnol. 2018, 9, 1423–1436, doi:10.3762/bjnano.9.135

• channels. More specifically, the solution flow conditions depend strongly on the structure of the porous medium. The specific pore size (or rather, the aspect ratio) depends on membrane thickness. A higher the aspect ratio results in restricted fluid flow. Therefore, the contact angle is also dependent

Perfusion double-channel micropipette probes for oxygen flux mapping with single-cell resolution

• Yang Gao,
• Bin Li,
• Riju Singhal,
• Adam Fontecchio,
• Ben Pelleg,
• Zulfiya Orynbayeva,
• Yury Gogotsi and
• Gary Friedman

Beilstein J. Nanotechnol. 2018, 9, 850–860, doi:10.3762/bjnano.9.79

• theta pipette and compare it with a finite element method (FEM) model that implements both Navier–Stokes equations to model the fluid flow and convection–diffusion equations to model molecular diffusion (see Experimental section for a detailed discussion). In the experiment, the fluid is being withdrawn

• represents roughly the diffusion boundary of the florescent dye. The arrows show the fluid flow direction. A constant withdraw rate of 5 µL/min is applied by a syringe pump to the pipette’s extraction channel. The injection pressure was increased from 100 hPa to 116 hPa with an increment of 2–3 hPa and then

Optimal fractal tree-like microchannel networks with slip for laminar-flow-modified Murray’s law

• Dalei Jing,
• Shiyu Song,
• Yunlu Pan and
• Xiaoming Wang

Beilstein J. Nanotechnol. 2018, 9, 482–489, doi:10.3762/bjnano.9.46

• widely studied and used in the fields of fluid flow, heat conduction, and heat convection [6][7][8][9][10][11][12][13][14][15][16][17][18]. For fluid flow, it is found that the fractal tree-like channel networks require less pumping power and have a smaller hydraulic resistance as compared with the

• conventional parallel channel systems under the constraint of the same channel volume. Furthermore, the optimal structure of the fractal tree-like channel networks for fluid flow to achieve minimum hydraulic resistance obeys the well-accepted Murray’s law in the manner of βm = NΔ, where βm is the diameter

• numerous theoretical and experimental studies, it is obtained under a no-slip condition assumption at the channel wall–liquid interface [12][14][15][16][17][18]. This no-slip condition assumption is reasonable for fluid flow in a macroscale channel, however, for a microscale channel, this assumption is

Interface conditions of roughness-induced superoleophilic and superoleophobic surfaces immersed in hexadecane and ethylene glycol

• Yifan Li,
• Yunlu Pan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2017, 8, 2504–2514, doi:10.3762/bjnano.8.250

• that can affect the drag of fluid flow. For surfaces with different oleophobicity, the boundary slip at the solid–oil interface is mostly larger than that at the solid–water interface. Roughness is a key factor for the wettability of superoleophilic/superoleophobic surfaces, and it has been found to

• liquid delivery in confined systems in biological, chemical and medical applications [1]. Interface conditions can affect fluid drag in micro/nanofluidic systems. First introduced by Navier, the slip boundary condition in hydrodynamics suggests that the velocity of fluid flow at a solid–liquid interface

• is not zero. There is a relative motion that can be expressed by the so-called slip length [2]. Previous studies have shown that the presence of boundary slip leads to lower drag for the fluid flow in micro/nanochannels [3][4][5]. Boundary slip has been studied experimentally and theoretically on

Numerical investigation of the tribological performance of micro-dimple textured surfaces under hydrodynamic lubrication

• Kangmei Li,
• Dalei Jing,
• Jun Hu,
• Xiaohong Ding and
• Zhenqiang Yao

Beilstein J. Nanotechnol. 2017, 8, 2324–2338, doi:10.3762/bjnano.8.232

• on the upper wall (see Figure 11a). When the aspect ratio is increased, it is found that the direction of fluid flow at the bottom of the micro-dimple is reversed to that of the upper wall, which implies the generation of a recirculation zone in the micro-dimple (see Figure 11b). With a further

A systematic study of the controlled generation of crystalline iron oxide nanoparticles on graphene using a chemical etching process

• Peter Krauß,
• Jörg Engstler and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2017, 8, 2017–2025, doi:10.3762/bjnano.8.202

• adhesive tape (e.g., tesa tape from Tesa SE), which protects the exposed edges of the synthesized graphene layer on the copper substrate (see Supporting Information File 1, Figure S1). These are the sites where mechanical agitation by fluid flow of the etching liquid is strongest and often results in

Study of the correlation between sensing performance and surface morphology of inkjet-printed aqueous graphene-based chemiresistors for NO₂ detection

• F. Villani,
• C. Schiattarella,
• T. Polichetti,
• R. Di Capua,
• F. Loffredo,
• B. Alfano,
• M. L. Miglietta,
• E. Massera,
• L. Verdoliva and
• G. Di Francia

Beilstein J. Nanotechnol. 2017, 8, 1023–1031, doi:10.3762/bjnano.8.103

• enriched up to the final concentration of 0.2 mg/mL (see the procedure described in the Experimental section). The physico-chemical properties of this final formulation have been investigated in order to establish if it satisfies the physical and rheological requirements of the fluid flow in the inkjet

The hydraulic mechanism in the hind wing veins of Cybister japonicus Sharp (order: Coleoptera)

• Jiyu Sun,
• Wei Wu,
• Mingze Ling,
• Bharat Bhushan and
• Jin Tong

Beilstein J. Nanotechnol. 2016, 7, 904–913, doi:10.3762/bjnano.7.82

• (CFD) solver. To simulate the insect wing veins within the fluid flow during the unfolding process, the CFD solver, FLUENT 6.3.26, was used to solve the momentum conservation equations (Navier–Stokes equation, NS equation) based on the pressure method. The motion of an unfolding wing was modeled by

• using the dynamic mesh technique. Assuming that the flow is laminar, the fluid medium is blood, and the inlet effect is not considered, the control equation of fluid flow in the beetle hind wing is the 3-D incompressible NS equation: where u, v, w are the velocity components (m/s) for the x, y, z

Contact-free experimental determination of the static flexural spring constant of cantilever sensors using a microfluidic force tool

• John D. Parkin and
• Georg Hähner

Beilstein J. Nanotechnol. 2016, 7, 492–500, doi:10.3762/bjnano.7.43

• measurements, the channel was fixed on the sample stage of the AFM and positioned such that fluid flow from its exit interacted with the cantilever as illustrated in Figure 1. The channel was aligned such that the free end of the cantilever was level with the edge of the channel and 100 μm above the channel

• cantilever studied. The highest pressure used was ≈3.5 kPa, resulting in a nitrogen velocity value of about ≈62 m/s in the channel mid-line [28], corresponding to a laminar, incompressible flow [36]. The forces applied to the cantilever by the fluid flow cause a static flexural bending [30]. The bending of

• microscope. Some of the cantilevers had a trapezoidal cross-section (see Figure 2), in which case both the width at the top and the bottom were determined. Determination of the force distribution and the conversion factors α, β, and γ To provide information about the interaction between the fluid flow

Single-molecule mechanics of protein-labelled DNA handles

• Vivek S. Jadhav,
• Dorothea Brüggemann,
• Florian Wruck and
• Martin Hegner

Beilstein J. Nanotechnol. 2016, 7, 138–148, doi:10.3762/bjnano.7.16

• approx. 2 min. For proof-of-concept that the PDH end remains freely accessible in liquids, the biotin end of the DH was labelled with streptavidin–Qdot conjugates. Then, they were anchored to anti-DIG beads (Figure 1f), and the position of individual Qdots under varying fluid flow velocities was

• monitored using an EMCCD camera (Andor Technology, Belfast, NI). Laminar fluid flow inside the microfluidic chamber constrained the free Qdot-modified end of the DNA within the image plane of the EMCCD camera (Figure 8). The distance between the bead surface and the position of the Qdot represented the

• fluid-flow dependent DNA extension, corresponding to the hydrodynamic drag experienced by the DNA molecule. The flow force induced stretching as presented here is consistent with the original experimental findings by Perkins et al. [15] and follows the theoretical description of Stigter et al. [16

Electroviscous effect on fluid drag in a microchannel with large zeta potential

• Dalei Jing and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2015, 6, 2207–2216, doi:10.3762/bjnano.6.226

• /bjnano.6.226 Abstract The electroviscous effect has been widely studied to investigate the effect of surface charge-induced electric double layers (EDL) on the pressure-driven flow in a micro/nano channel. EDL has been reported to reduce the velocity of fluid flow and increase the fluid drag

• ]. Understanding the fundamental mechanisms of the micro/nano fluid flow has inspired wide scientific interest in order to accomplish the manipulation and transportation of micro/nano fluid flow in these micro/nano fluidic devices. Theoretical and experimental studies show that some interfacial properties, such as

• surface charge, boundary slip, nanobubble and surface roughness, which can be neglected in macroscale fluidics, are believed to significantly affect the micro/nano fluid flow [3][4][5][6][7][8][9][10][11][12][13]. When a droplet of certain liquid contacts with a solid surface, the solid–liquid interface

Hydrophobic interaction governs unspecific adhesion of staphylococci: a single cell force spectroscopy study

• Nicolas Thewes,
• Peter Loskill,
• Philipp Jung,
• Henrik Peisker,
• Markus Bischoff,
• Mathias Herrmann and
• Karin Jacobs

Beilstein J. Nanotechnol. 2014, 5, 1501–1512, doi:10.3762/bjnano.5.163

• corresponding binding partners are available. The adhesion process of microorganisms, such as S. carnosus, is usually characterized by using flow chambers [14]. Although flow chamber studies reproduce the natural adsorption process of microorganisms out of fluid flow, it is hard to determine quantitative

The study of surface wetting, nanobubbles and boundary slip with an applied voltage: A review

• Yunlu Pan,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2014, 5, 1042–1065, doi:10.3762/bjnano.5.117

• The drag of fluid flow at the solid–liquid interface in the micro/nanoscale is an important issue in micro/nanofluidic systems. Drag depends on the surface wetting, nanobubbles, surface charge and boundary slip. Some researchers have focused on the relationship between these interface properties. In

• force on the probe were measured on an octadecyltrichlorosilane (OTS) surface with applied voltage. The influence of the surface charge on the boundary slip and drag of fluid flow has been discussed. Finally, the influence of the applied voltage on the surface wetting, nanobubbles, surface charge

• various groups [10][12][15][23][24][25][26]. Most studies have a similar goal that is to find a method to affect the boundary slip condition by increasing the boundary slip length, which then reduces the drag of fluid flow. Recently, it is found that a higher hydrophobicity can provide a larger slip