scholarly journals Three-dimensional two-component velocity measurement of the flow field induced by theVorticella pictamicroorganism using a confocal microparticle image velocimetry technique

2009 ◽  
Vol 3 (1) ◽  
pp. 014105 ◽  
Author(s):  
Moeto Nagai ◽  
Masamichi Oishi ◽  
Marie Oshima ◽  
Hiroshi Asai ◽  
Hiroyuki Fujita
Keyword(s):  
Flow Field ◽  
Velocity Measurement ◽  
Three Dimensional ◽  
Image Velocimetry ◽  
Two Component ◽  
Microparticle Image Velocimetry ◽  
Component Velocity

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.

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).

Experimental Analysis of Microchannel Entrance Length Characteristics Using Microparticle Image Velocimetry

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Tariq Ahmad ◽  
Ibrahim Hassan
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Entrance Region ◽  
Working Fluid ◽  
Parallel Plates ◽  
Entrance Length ◽  
Number Range ◽  
Micro Piv ◽  
Image Velocimetry ◽  
Microparticle Image Velocimetry

The study of the entrance region of microchannels and microdevices is limited, yet important, since the effect on the flow field and heat transfer mechanisms is significant. An experimental study has been carried out to explore the laminar hydrodynamic development length in the entrance region of adiabatic square microchannels. Flow field measurements are acquired through the use of microparticle image velocimetry (micro-PIV), a nonintrusive particle tracking and flow observation technique. With the application of micro-PIV, entrance length flow field data are obtained for three different microchannel hydraulic diameters of 500 μm, 200 μm, and 100 μm, all of which have cross-sectional aspect ratios of 1. The working fluid is distilled water, and velocity profile data are acquired over a laminar Reynolds number range from 0.5 to 200. The test-sections were designed as to provide a sharp-edged microchannel inlet from a very large reservoir at least 100 times wider and higher than the microchannel hydraulic diameter. Also, all microchannels have a length-to-diameter ratio of at least 100 to assure fully developed flow at the channel exit. The micro-PIV procedure is validated in the fully developed region with comparison to Navier–Stokes momentum equations. Good agreement was found with comparison to conventional entrance length correlations for ducts or parallel plates, depending on the Reynolds range, and minimal influence of dimensional scaling between the investigated microchannels was observed. New entrance length correlations are proposed, which account for both creeping and high laminar Reynolds number flows. These correlations are unique in predicting the entrance length in microchannels and will aid in the design of future microfluidic devices.

Three Component Velocity Measurements in the Interblade Region of a Fan

1987 ◽  
Author(s):  
Rajan K. Menon
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Swirl Flow ◽  
Cross Sectional ◽  
Position Information ◽  
Non Invasive ◽  
Orthogonal Components ◽  
Component Velocity ◽  
Efficient Power ◽  
Three Components

Optimizing aerodynamics and improving blade designs to make efficient power-generating machinery requires a good understanding of the rotor flow field. Swirl, flow instabilities, and high turbulence highlight the need for understanding the three-dimensional nature of the flow. Dynamic interaction between fluid and structural aspects in fluid machinery, impact of unsteady flows or loads, and enhancement of property transport can be studied through simultaneous measurement of three components of velocity. A three color, three component Laser Velocimeter System is used to simultaneously measure the three orthogonal components of velocity in the interblade region of a fan. The non-invasive nature of the technique combined with the very small measuring volume of the system provides detailed mapping of the flow field in the interblade region. The data acquisition package collects all the data available while the machine is running and sorts the raw data into bins corresponding to the various circumferential positions. Each velocity measurement — all three components — along with the circumferential position information is collected by a DEC PDP 11/23 Computer. The analysis package allows the user to examine a portion of the interblade region, look at alternate interblade gaps, omit data during blade passage, etc. Statistical properties such as mean, turbulence, skewness, flatness, Reynolds stress values, and projections in cross sectional planes are obtained and displayed as a function of circumferential position. Thus, the detailed properties of the three dimensional flow field are obtained from the three component LDV measurements.

Measurements and simulations of time-dependent flow fields within an electrokinetic micromixer

2011 ◽  
Vol 676 ◽  
pp. 265-293 ◽  
Author(s):  
DOMINIK P. J. BARZ ◽  
HAMID FARANGIS ZADEH ◽  
PETER EHRHARD
Keyword(s):  
Flow Field ◽  
Base Flow ◽  
Complex Flow ◽  
Flow Topology ◽  
Electrical Field ◽  
Image Velocimetry ◽  
Microparticle Image Velocimetry ◽  
Meander Bends ◽  
Dependent Flow ◽  
Meander Channel

We investigate the flow field in an electrokinetic micromixer. The concept of the micromixer is based on the combination of an alternating electrical field applied to a pressure-driven base flow in a meander–channel geometry. The presence of the electrical field leads to an additional electro-osmotic velocity contribution, which results in a complex flow field within the meander bends. The velocity fields within the meander are measured by means of a microparticle-image velocimetry method. Furthermore, we introduce a mathematical model, describing the electrical and fluid-mechanical phenomena present within the device, and perform simulations comparable to the experiments. The comparison of simulations and experiments reveals good agreement, with minor discrepancies in flow topology, obviously caused by small but crucial differences between experimental and numerical geometries. In detail, simulations are performed for sharp corners of the bends, while in the experiments these corners are rounded due to the microfabrication process.

Measurement of the Three-Dimensional Tip Region Flow Field in an Axial Compressor

1993 ◽  
Vol 115 (3) ◽  
pp. 468-476 ◽  
Author(s):  
R. C. Stauter
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Time Resolved ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Rotating Blade ◽  
Flow Phenomena ◽  
Component Velocity ◽  
And Behavior

A two-color, five-beam LDV system has been configured to make simultaneous three-component velocity measurements of the flow field in a two-stage axial compressor model. The system has been used to make time-resolved measurements both between compressor blade rows and within the rotating blade passages in an axial compressor. The data show the nature and behavior of the complex, three-dimensional flow phenomena present in the tip region of a compressor as they convect downstream. In particular, the nature of the tip leakage vortex is apparent, being manifested by high blockage as well as the expected vortical motion. The data indicate that the radial flows associated with the tip leakage vortex begin to decrease while within the rotor passage, and that they temporarily increase aft of the passage.

The Application of Particle Image Velocimetry (PIV) in a Short-Duration Transonic Annular Turbine Cascade

1992 ◽  
Vol 114 (3) ◽  
pp. 504-509 ◽  
Author(s):  
P. J. Bryanston-Cross ◽  
C. E. Towers ◽  
T. R. Judge ◽  
D. P. Towers ◽  
S. P. Harasgama ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Short Duration ◽  
Particle Image ◽  
Guide Vane ◽  
Three Dimensional ◽  
Film Plane ◽  
Test Facility ◽  
Image Velocimetry

A series of experiments have been performed to demonstrate the application of Particle Image Velocimetry (PIV) to turbomachinery flows. The tests were performed at transonic speeds on a fully annular engine size turbine nozzle guide vane. The vane cascade was installed in a short-duration Isentropic Light Piston Cascade (ILPC) test facility operating with high inlet turbulence levels. The technique has been shown to map the whole flow field with a resolution of 0.5 mm. The quality of the results obtained is not significantly affected by local turbulence rates. The accuracy of the measurements is put at around 4 percent of absolute velocity and is limited by the quality of the image on the film plane. The velocities derived from the PIV images have been compared with predictions from a three-dimensional viscous numerical calculation. It is shown that the experimental and predicted results are in good agreement. It is considered that this technique has considerable potential in application to turbomachinery flow field diagnostics.

PIV on Inclined Cylinder Shaped Fish Cages in a Current and the Resulting Flow Field

2008 ◽  
Author(s):  
Astrid Harendza ◽  
Jan Visscher ◽  
Lars Gansel ◽  
Bjo̸rnar Pettersen
Keyword(s):  
Flow Field ◽  
Particle Image ◽  
Three Dimensional ◽  
Structure Change ◽  
Fish Farms ◽  
Three Dimensional Flow ◽  
Towing Tank ◽  
Image Velocimetry ◽  
Fish Cages ◽  
A Current

The present experimental investigation focuses on the flow structure around short free end cylinders with an aspect ratio of L/D = 3 at a Reynolds number of Re = 5000. Cylinders with varying degrees of inclination and porosity were tested in a towing tank, acting as models for fish farm cages. According to studies of fish cages at commercial Norwegian fish farms, the inclination angle of the structure change up to 25 degrees from the vertical when exposed to a current. Cylinders with porosities of 0% and 75% were tested, the latter representing fish cage netting with fouling. To visualize the flow around the cylinders, 2- and 3-Component (2C and 3C) Particle Image Velocimetry (PIV) was used. The effects of inclination and porosity on the three-dimensional flow field will be described and discussed.

Three-Dimensional Measurement of the Hydrocyclone Flow Field Using V3V

2014 ◽  
Vol 595 ◽  
pp. 209-214
Author(s):  
Jian Gang Wang ◽  
Hua Lin Wang ◽  
Xu Duan
Keyword(s):  
Flow Field ◽  
Radial Velocity ◽  
Three Dimensional ◽  
Huge Amount ◽  
Matching Method ◽  
Dimensional Measurement ◽  
Index Matching ◽  
Two Component ◽  
Three Dimensional Measurement ◽  
Refractive Index Matching

The three dimensional three component (3D3C) flow field inside hydrocyclone was investigated using Volumetric 3-component Velocimetry (V3V). To improve the spatial resolution of the measurement, a refractive index matching method is used in the experiment. The three components of the velocity in the hydrocyclonic flow is measured, and the measurement produced huge amount of data, which enabled detailed analysis of the hydrocyclonic flow field. The tangential and axial is quasi-symmetric while the radial velocity is non-axisymmetric. The radial velocity is one order smaller in value than the other two component. Results show V3V with index matching is a robust method to the measurement of hydrocyclone flow field.

scholarly journals Intracavity Rayleigh-Mie scattering for multipoint, two-component velocity measurement

2006 ◽  
Vol 31 (11) ◽  
pp. 1645 ◽  
Author(s):  
Daniel Bivolaru ◽  
Paul M. Danehy ◽  
Joseph W. Lee
Keyword(s):  
Velocity Measurement ◽  
Mie Scattering ◽  
Two Component ◽  
Component Velocity
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