scholarly journals Levitating spherical particle in a slightly tapered tube at low Reynolds numbers: Application to the low-flow rate rotameters

2012 ◽  
Vol 83 (12) ◽  
pp. 125103
Author(s):  
S. Champmartin ◽  
A. Ambari ◽  
R. P. Chhabra
Keyword(s):  
Spherical Particle ◽  
Flow Rate ◽  
Reynolds Numbers ◽  
Low Flow ◽  
Low Reynolds Numbers ◽  
Low Reynolds ◽  
Low Flow Rate

scholarly journals Hydrodynamic particle focusing enhanced by femtosecond laser deep grooving at low Reynolds numbers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tianlong Zhang ◽  
Misuzu Namoto ◽  
Kazunori Okano ◽  
Eri Akita ◽  
Norihiro Teranishi ◽  
...  
Keyword(s):  
Flow Rate ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Low Flow ◽  
Live Cells ◽  
Low Reynolds Numbers ◽  
Particle Focusing ◽  
Human T Cell ◽  
Fs Laser ◽  
Low Reynolds

AbstractMicrofluidic focusing of particles (both synthetic and biological), which enables precise control over the positions of particles in a tightly focused stream, is a prerequisite step for the downstream processing, such as detection, trapping and separation. In this study, we propose a novel hydrodynamic focusing method by taking advantage of open v-shaped microstructures on a glass substrate engraved by femtosecond pulse (fs) laser. The fs laser engraved microstructures were capable of focusing polystyrene particles and live cells in rectangular microchannels at relatively low Reynolds numbers (Re). Numerical simulations were performed to explain the mechanisms of particle focusing and experiments were carried out to investigate the effects of groove depth, groove number and flow rate on the performance of the groove-embedded microchannel for particle focusing. We found out that 10-µm polystyrene particles are directed toward the channel center under the effects of the groove-induced secondary flows in low-Re flows, e.g. Re < 1. Moreover, we achieved continuous focusing of live cells with different sizes ranging from 10 to 15 µm, i.e. human T-cell lymphoma Jurkat cells, rat adrenal pheochromocytoma PC12 cells and dog kidney MDCK cells. The glass grooves fabricated by fs laser are expected to be integrated with on-chip detection components, such as contact imaging and fluorescence lifetime-resolved imaging, for various biological and biomedical applications, where particle focusing at a relatively low flow rate is desirable.

Low Reynolds-Number Experiments in an Axial-Flow Turbomachine

1964 ◽  
Vol 86 (3) ◽  
pp. 257-295 ◽  
Author(s):  
J. Neustein
Keyword(s):  
Reynolds Number ◽  
Guide Vane ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Low Flow ◽  
Working Fluid ◽  
Low Reynolds Numbers ◽  
Blade Row ◽  
Overall Performance ◽  
Low Reynolds

The performance of a single-stage, axial-flow turbomachine was studied experimentally at low Reynolds numbers. The study was made with a turbomachine modeled from a large jet-engine type of axial-flow compressor. Low Reynolds numbers were obtained by using a mixture of glycerine and water as the working fluid. The overall performance was determined over a range of Reynolds numbers RT (based on rotor-tip speed and rotor chord) from 2000 to 150,000. The flow rate at each Reynolds number was varied from near shutoff to the maximum permitted by the turbomachine-tunnel systems. Blade-row characteristics were studied by means of quantitative flow surveys before and after each blade row, and by means of extensive flow-visualization experiments within each blade row. The investigation established that sudden or critical changes in performance do not occur in the type of machine tested, between RT of 150,000 and 20,000. Below 20,000 the performance deteriorated more rapidly. A relatively sharp change in performance occurred between RT of 20,000 and 10,000. The results clarified many of the viscous flow details in each blade row which are associated with the deterioration of performance. These effects were very pronounced at RT of 4000 and below. Consequently, a considerable part of the paper is concerned with results obtained at these lower Reynolds numbers. From the point of view of a designer, information is presented in regard to overall performance, guide-vane turning, and guide-vane and stator total-pressure losses, all as functions of Reynolds number. These results are expected to be indicative of performance in turbomachines similar to the one tested here. Other details are concerned with problems such as wall boundary layers, flow reversal at low flow coefficients, lip-clearance flow, flow patterns near shutoff, and flow comparisons in stators with rotating and stationary hubs.

scholarly journals Effect of the inlet flow rate ratio on liquid efficiency in a T-shaped micromixer at low Reynolds numbers

2020 ◽  
Vol 1677 ◽  
pp. 012138
Author(s):  
A Yu Kravtsova ◽  
M V Kashkarova ◽  
P E Ianko ◽  
A V Bilsky ◽  
Y V Kravtsov
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Reynolds Numbers ◽  
Flow Rate Ratio ◽  
Inlet Flow ◽  
Low Reynolds Numbers ◽  
Inlet Flow Rate ◽  
Low Reynolds

scholarly journals The Effects of a Constant Bias Force on the Dynamics of a Periodically Forced Spherical Particle in a Newtonian Fluid at Low Reynolds Numbers

2010 ◽  
Author(s):  
K. Madhukar ◽  
T. R. Ramamohan ◽  
I. S. Shivakumara ◽  
Theodore E. Simos ◽  
George Psihoyios ◽  
...  
Keyword(s):  
Spherical Particle ◽  
Newtonian Fluid ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Constant Bias ◽  
Low Reynolds

A Reassessment of Metering Orifices for Low Reynolds Numbers

1965 ◽  
Vol 180 (1) ◽  
pp. 331-356 ◽  
Author(s):  
L. J. Kastner ◽  
J. C. McVeigh
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
Low Reynolds Number ◽  
Reynolds Numbers ◽  
Number Range ◽  
Low Reynolds Numbers ◽  
Discharge Coefficients ◽  
Low Reynolds

In view of the importance of accurate measurement of flow rate at low Reynolds numbers, there have been numerous attempts to develop metering devices having constant discharge coefficients in the range of pipe Reynolds numbers between about 3000 and 200 and even below this latter value, and some of these attempts have achieved a reasonable degrees of success. Nevertheless, some confusion exists regarding the dimensions and range of utility of certain designs which have been recommended and further information is necessary in order that the situation may be clarified. The aims of the present investigation, which is believed to be wider in scope than any published in this field in recent years, were to review and correlate existing knowledge and to make an experimental study of the properties of various types of orifice in the low range of Reynolds numbers. Arising from this it was hoped that a design might be evolved which not only had a satisfactorily constant discharge coefficient throughout the range but was also simple to manufacture and reproduce, even for small orifice diameters of the order of 0.5 in or less, and it is believed that some success in attaining this aim was achieved. The first section of the paper contains a review of previous investigations classified into three main groups. In the second part of the paper, experiments with various types of orifice plate are described and it is shown that a properly proportioned single-bevelled orifice has as good a performance in the low Reynolds number range as that of any of the more complicated shapes.

scholarly journals No net motion for oscillating near-spheres at low Reynolds numbers

2019 ◽  
Vol 866 ◽  
Author(s):  
K. Lippera ◽  
O. Dauchot ◽  
S. Michelin ◽  
M. Benzaquen
Keyword(s):  
Spherical Particle ◽  
Acoustic Streaming ◽  
Reynolds Numbers ◽  
Higher Order ◽  
Low Reynolds Numbers ◽  
Low Reynolds

We investigate the flow around an oscillating nearly spherical particle at low, yet non-vanishing, Reynolds numbers ($Re$), and the potential resulting locomotion. We analytically demonstrate that no net motion can arise up to order one in $Re$ and order one in the asphericity parameter, regardless of the particle’s shape. Therefore, geometry-induced acoustic streaming propulsion, if any, must arise at higher order.

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