scholarly journals Numerical and Experimental Analyses of Three-Dimensional Unsteady Flow Around a Micro-Pillar Subjected to Rotational Vibration

2018 ◽  
Author(s):  
Kanji Kaneko ◽  
Takayuki Osawa ◽  
Yukinori Kametani ◽  
Takeshi Hayakawa ◽  
Yosuke Hasegawa ◽  
...  
Keyword(s):  
Flow Field ◽  
Moving Boundary ◽  
Three Dimensional ◽  
Steady Streaming ◽  
Micro Particle Image Velocimetry ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Measurement Tools ◽  
Rotational Vibration ◽  
Induced Flow

The steady streaming (SS) phenomenon is gaining increased attention in the microfluidics community, because it can generate net mass flow from the zero-mean vibration. We developed numerical simulation and experimental measurement tools to analyze this vibration induced flow, which has been challenging due to its unsteady nature. Validity of these analysis methods is confirmed by comparing the three-dimensional (3D) flow field induced around a cylindrical micropillar under circular vibration. In the numerical modeling, we directly solved the flow in the Lagrangian frame so that the substrate with a micropillar becomes stationary, and the result was converted to the Eulerian frame to compare them with the experimental results. The present approach enables to avoid the introduction of moving boundary or small perturbation approximation. The flow field obtained by the micro particle image velocimetry (PIV) measurement supported the three-dimensionality observed in the numerical results, which could be important for controlling the mass transport and manipulating particulate objects in the microfluidic systems.

scholarly journals Numerical and Experimental Analyses of Three- Dimensional Unsteady Flow around a Micro-Pillar Subjected to Rotational Vibration

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 668 ◽  
Author(s):  
Kanji Kaneko ◽  
Takayuki Osawa ◽  
Yukinori Kametani ◽  
Takeshi Hayakawa ◽  
Yosuke Hasegawa ◽  
...  
Keyword(s):  
Flow Field ◽  
Moving Boundary ◽  
Three Dimensional ◽  
Steady Streaming ◽  
Micro Piv ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Measurement Tools ◽  
Rotational Vibration ◽  
Induced Flow

The steady streaming (SS) phenomenon is gaining increased attention in the microfluidics community, because it can generate net mass flow from zero-mean vibration. We developed numerical simulation and experimental measurement tools to analyze this vibration-induced flow, which has been challenging due to its unsteady nature. The validity of these analysis methods is confirmed by comparing the three-dimensional (3D) flow field and the resulting particle trajectories induced around a cylindrical micro-pillar under circular vibration. In the numerical modeling, we directly solved the flow in the Lagrangian frame so that the substrate with a micro-pillar becomes stationary, and the results were converted to a stationary Eulerian frame to compare with the experimental results. The present approach enables us to avoid the introduction of a moving boundary or infinitesimal perturbation approximation. The flow field obtained by the micron-resolution particle image velocimetry (micro-PIV) measurement supported the three-dimensionality observed in the numerical results, which could be important for controlling the mass transport and manipulating particulate objects in microfluidic systems.

Micro Rod Mixer Using AC Electric Field Induced Flow

2011 ◽  
Author(s):  
Hiromichi Obara ◽  
Shinichi Tashiro
Keyword(s):  
Electric Field ◽  
Flow Structure ◽  
Three Dimensional ◽  
Flow Structures ◽  
Micro Scale ◽  
Micro Particle Image Velocimetry ◽  
Source Type ◽  
Ac Electric Field ◽  
Image Velocimetry ◽  
Induced Flow

A novel rod mixer, using a micro-scale flow structure induced with electrokinetics under an AC electric field, is proposed for three-dimensional micro-scale processing of biological applications. Flow structures around the micro-rod mixer are demonstrated using the micro-particle image velocimetry method and the particle-tracking velocimetry method. Characteristics of the flow structure and mixing property are investigated for several electric field intensities and frequencies. It is observed that the micro-mixing flow structures induced with an AC electric field at the appropriate intensity and frequency conditions which are intermediate conditions between a dielectrophoresis and an electrolysis. A source-type three-dimensional flow structure is generated around the tip of the micro-rod electrode installed in the sample liquid. Furthermore it is possible to control the scale of the flow structure by adjusting the supplied AC electric field intensity and frequency. The mixing characteristics are also discussed.

Experimental investigation on the momentumless wake using trailing edge blowing

2008 ◽  
Vol 222 (8) ◽  
pp. 1477-1486 ◽  
Author(s):  
Y Wu ◽  
X Zhu ◽  
Z Du
Keyword(s):  
Three Dimensional ◽  
Velocity Profiles ◽  
Axial Fan ◽  
Trailing Edge ◽  
Mean Velocity ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Velocity Spectra ◽  
Momentumless Wake ◽  
Wake Characteristics

A developed plate stator model with and without trailing edge blowing (TEB) is studied using experimental methods. Wake characteristics of flow over the stator in the three-dimensional wake regimes are studied using hot-wire anemometry (HWA) and particle image velocimetry (PIV) techniques. First, the mean velocity profiles have been measured in the wake of the stator using HWA. Four wake characteristics have been obtained through momentum thickness judgments: pure wake, weak wake, momentumless wake, and jet. These velocity profiles show some differences in momentum deficit for the four cases. Then, the velocity spectra of the pure wake and momentumless wake obtained through the HWA measurements showed that TEB can eliminate the shedding vortex of the stator. Characteristic length scales based on the wake turbulent intensity profiles showed that the momentumless wake can reduce the wake width and depth. PIV measurement is carried out to measure the flow field of the four wakes. Finally, the application of TEB approaching momentumless wake status is used on an industrial ventilation low-pressure axial fan to assess noise reduction. The results show that TEB can make the outlet of the stator uniform, reduce velocity fluctuation, destroy the vorticity structure downstream of the stator, and reduce interaction noise level of the stator and rotor.

Feasibility Study on Application of a Self-Formed Flow Field Downstream of Elbows to Divertor Cooling

2013 ◽  
Author(s):  
Shoichi Kodate ◽  
Tatsuya Kubo ◽  
Shinji Ebara ◽  
Hidetoshi Hashizume
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Reynolds Stress ◽  
Swirling Flow ◽  
Pipe Wall ◽  
Three Dimensional ◽  
High Heat ◽  
Turbulent Pipe Flow ◽  
High Heat Transfer ◽  
Piv Measurement

In this study, the characteristic of the swirling flow was analyzed in detail in terms of flow field by means of a visualization experiment using matched refractive index PIV measurement to evaluate the applicability of the swirling flow generated downstream of a three-dimensionally connected dual elbow to the divertor cooling. The dual elbow used in the experiment comprises two 90-degree elbows with the same curvature connected directly in three-dimensional configuration. From the experiment, it was found that strong swirling velocity component appears locally near the pipe wall downstream of the second elbow. Moreover, although the strength of the swirling flow changed gradually as it flowed downstream, it attenuated little even 8D downstream of the dual elbow, where D was the diameter of the piping. Therefore, this swirling flow is expected to survive for a considerable distance downstream of the elbow, and the applicability of this flow field to divertor cooling can be promising. Furthermore turbulence quantities such as Reynolds stress were analyzed in terms of heat transfer performance. Since there were some regions where larger Reynolds stress than a developed turbulent pipe flow was observed near the pipe wall, high heat transfer is expected there.

Three-Dimensional Micro-Flow Measurement in a Capillary with a Diode Laser Micro-Particle Image Velocitometry

2006 ◽  
Vol 505-507 ◽  
pp. 343-348
Author(s):  
C.T. Pan ◽  
P.J. Cheng ◽  
Yeong-Maw Hwang ◽  
M.F. Chen ◽  
H.S. Chuang ◽  
...  
Keyword(s):  
Diode Laser ◽  
Particle Image ◽  
Three Dimensional ◽  
Calibration Method ◽  
Measurement Range ◽  
Scanning Method ◽  
Micro Particle Image Velocimetry ◽  
Micro Piv ◽  
Image Velocimetry ◽  
Micro Flow

A self-built micro-particle image velocimetry (micro-PIV) with a diode laser is established to measure the micro-fluidic phenomenon in a 100 μm rectangular capillary. By scanning method, a 3-D flow image with a flowrate of 0.3 μL/min is presented. With this calibration method, the measurement ability for 3-D micro-fluidic dynamics could be achieved. This technique also reveals its benefit and potential in metrology. Hence, it provides a helpful tool for Bio-MEMS research. The experiment is proceeded under laminar flow, Re= 0.011. The measurement range is ranging from 0.05μm/s to 4.3mm/s. The vector grid resolution is optimized to 2.5 μm.

scholarly journals Simultaneous Measurement of Free Surface Elevation and Three-Component Velocity Field Around a Translating Surface-Piercing Foil

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
James Schock ◽  
Jason Dahl
Keyword(s):  
Particle Image Velocimetry ◽  
Free Surface ◽  
Velocity Field ◽  
Numerical Methods ◽  
Flow Field ◽  
Particle Image ◽  
Laser Sheet ◽  
Three Dimensional ◽  
Dynamic Mode ◽  
Image Velocimetry

Two methods are investigated to simultaneously obtain both three-dimensional (3D) velocity field and free surface elevations (FSEs) measurements near a surface piercing foil, while limiting the equipment. The combined velocity field and FSE measurements are obtained specifically for the validation of numerical methods requiring simultaneous field data and free surface measurements for a slender body shape. Both methods use stereo particle image velocimetry (SPIV) to measure three component velocities in the flow field and both methods use an off the shelf digital camera with a laser intersection line to measure FSEs. The first method is performed using a vertical laser sheet oriented parallel to the foil chord line. Through repetition of experiments with repositioning of the laser, a statistical representation of the three-dimensional flow field and surface elevations is obtained. The second method orients the vertical laser sheet such that the foil chord line is orthogonal to the laser sheet. A single experiment is performed with this method to measure the three-dimensional three component (3D3C) flow field and free surface, assuming steady flow conditions, such that the time dimension is used to expand the flow field in 3D space. The two methods are compared using dynamic mode decomposition and found to be comparable in the primary mode. Utilizing these methods produces results that are acceptable for use in numerical methods verification, at a fraction of the capital and computing cost associated with two plane or tomographic particle image velocimetry (PIV).

Measurement of 3D Flow Structure of Viscoelastic Fluid Using Digital Holographic Microscope

2015 ◽  
Author(s):  
Xiao-Bin Li ◽  
Masamichi Oishi ◽  
Tsukasa Matsuo ◽  
Marie Oshima ◽  
Feng-Chen Li ◽  
...  
Keyword(s):  
Flow Field ◽  
Real Time ◽  
Viscoelastic Fluid ◽  
Three Dimensional ◽  
Complex Flow ◽  
Micro Particle Image Velocimetry ◽  
Dimensional Measurement ◽  
Tracer Particles ◽  
Three Dimensional Measurement ◽  
Measured Flow

This paper aims to develop a three-dimensional measurement approach to investigate the flow structures of viscoelastic fluid in the curved microchannel by using digital holographic microscope (DHM). With the advantage of DHM, the real-time three-dimensional measurement for the complex flow field can be accomplished. The measurment system uses off-axis holographic / interferometric optical setup for the target, and 3D3C particle tracking velocimetry (PTV) can be achieved based on the analysis of phase information of holograms. To diagnose the chaotic flow inside the microchannel, the 3D temporal positions of tracer particles in the volume of 282μm × 282μm × 60μm have been detected and real-time velocity vectors were calculated based on the PTV algorithm. The measured flow field was then compared with the results obtained by using confocal micro particle image velocimetry (PIV). This technique is proven to be successful for the measurements of microfluidic flow, especially for the truly real-time 3D motions.

Sign in / Sign up

Export Citation Format

Share Document