PIV Analysis of Instantaneous Flow Structures in an Inkjet Printhead

1999 ◽  
Author(s):  
Hongsheng Zhang ◽  
Carl D. Meinhart
Keyword(s):  
Particle Image ◽  
Fluid Velocity ◽  
Ccd Camera ◽  
Velocity Fields ◽  
Flow Structures ◽  
Instantaneous Flow ◽  
Piv Technique ◽  
Image Velocimetry ◽  
Piv Analysis ◽  
Inkjet Printhead

Abstract This paper presents experimental measurements and observations of instantaneous flow structures inside an inkjet printhead, using a micron-resolution Particle Image Velocimetry (PIV) system to record visualized flows and calculate velocity fields. The PIV technique uses 700 nm diameter fluorescent flow-tracing particles, a pulsed Nd:YAG laser, an epi-fluorescent microscope and an interline-transfer CCD camera to record images of a flow at two successive instances in time. By measuring how far a set of particles move during a specified duration of time, an estimate of the local fluid velocity can be obtained. An electronic timing strategy has been developed to synchronize the PIV lasers, the CCD camera and the drop ejection system. An overall flow pattern during a 500 μs ejection cycle has been observed by phase-averaging hundreds of instantaneous velocity fields, which were recorded at 2–5 μs intervals throughout the cycle. A velocity field with spatial resolution of approximately 10 μm was obtained near the inkjet nozzle. Meniscus and nodes inside the printhead were also observed and recorded.

scholarly journals Novel analysis for large strains based on particle image velocimetry

2017 ◽  
Vol 54 (7) ◽  
pp. 933-944 ◽  
Author(s):  
Núria M. Pinyol ◽  
Mauricio Alvarado
Keyword(s):  
Particle Image Velocimetry ◽  
Slope Failure ◽  
Particle Image ◽  
Large Strains ◽  
Software Packages ◽  
Piv Technique ◽  
Standard Procedures ◽  
Image Velocimetry ◽  
Sandy Slope ◽  
Piv Analysis

Over the last few decades, the particle image velocimetry (PIV) technique has become an interesting tool used to measure displacements in the field of experimental mechanics. This paper presents a procedure to interpret PIV displacements, measured following an Eulerian scheme, with the purpose of providing accumulated displacements, velocities, accelerations, and strains on points representing physical particles. Strains are computed as the gradient of displacements. When compared with other standard procedures already published, the presented methodology is especially well suited to interpret large strains. The basis of the procedure is to map displacement increments measured through PIV analysis on the subset (or patch) centres into numerical particles that are defined as portions of the moving masses whose deformation is analyzed. The implementation of the method is explained in detail, highlighting its simplicity. The procedure can be used as a post-processor of currently available PIV software packages. The methodology is first applied to synthetic cases of rectangular samples in which known displacements are imposed and also to a sandy slope failure experiment involving large displacements. The method reproduces satisfactorily the recorded images.

Flow Field Analysis of Dielectrophoretically-Suspended Particles

2007 ◽  
Author(s):  
Stuart J. Williams ◽  
Steven T. Wereley
Keyword(s):  
Electric Fields ◽  
Particle Image ◽  
Fluid Velocity ◽  
Microfluidic Channel ◽  
Velocity Fields ◽  
Field Analysis ◽  
Tracer Particles ◽  
Image Velocimetry ◽  
Flow Field Analysis ◽  
Complete Investigation

Understanding the fluid dynamics around a particle in suspension is important for a complete investigation of many hydrodynamic phenomena, including microfluidic models. A novel tool that has been used to analyze fluid velocity fields in microfluidics is micro-resolution particle image velocimetry (μPIV) [1]. Dielectrophoresis (DEP) is a technique that can translate and trap particles by induced polarization in the presence of nonuniform electric fields. In this paper, DEP has been used to capture and suspend a single 10.1μm diameter spherical particle in a microfluidic channel. μPIV is then used with smaller tracer particles (0.5μm) to investigate the hydrodynamics of fluid flow past the trapped particle.

Experimental Study of the Characteristics of Gas Impinging Streams Using PIV Technique

2013 ◽  
Author(s):  
Wei Wei ◽  
ZhiYi Li ◽  
Fengxia Liu ◽  
Zhijun Liu
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Velocity Fields ◽  
Experimental Equipment ◽  
Piv Technique ◽  
Tracer Particles ◽  
Image Velocimetry

Impinging streams technology has been widely used in many applications in recent years because of its enhancement to the heat and mass transfer between phases. In this paper, in order to investigate the influences of the impinging distance and flow rate on the characters of the flow field, gas-gas impinging streams flow fields are tested experimentally and analyze qualitatively with particle image velocimetry (PIV). The experimental equipment consists of two opposite nozzles which are the same axis. A PIV system is used to measure the characters of the 2-D flow field between two opposite nozzles. The gas is delivered by a compressor through two opposite jets which could be seeded with oil droplets as tracer particles. The effects of the flow rate and impinging distance on the velocity fields of impinging zone are investigated in detail. As the flow rate increases from 0.2 m3/h to 0.8 m3/h, the width of impinging zone increases from 0.25 to 0.5. However, the range of impinging zone does not change significantly as the impinging distance increases from 61mm to 94mm. The results indicate that the PIV technique is an effective method to measure and analyze the characters of impinging streams.

scholarly journals Experimental Investigation of Flow Structures Around side-by-side Yawed Cylinders in Shallow Water

2019 ◽  
Vol 2 (3) ◽  
pp. 1138-1151
Author(s):  
Ebubekir Kütük ◽  
Umutcan Olmuş ◽  
Tahir Durhasan ◽  
Hüseyin Akıllı
Keyword(s):  
Shear Stress ◽  
Shallow Water ◽  
Vector Fields ◽  
Particle Image ◽  
Reynolds Shear Stress ◽  
Flow Structures ◽  
Piv Technique ◽  
Gap Ratio ◽  
Image Velocimetry ◽  
Yaw Angle

The aim of this experimental study is to investigate the flow behaviour around two equally yawed side-by-side cylinders in shallow water. Time averaged velocity vector fields, Reynolds shear stress distrubutions and streamline patterns were obtained using Particle Image Velocimetry (PIV) technique. The gap ratio between the cylinders were in the range of G/D=0.25-1.25 with an increment of 0.25 where G is the distance between the cylinders and D is the cylinder diameter. Five different yaw angles of cylinders were employed during the experiment. The results showed that the yaw angle, α had an important effect on the flow structures of the downstream of the cylinders. Reynolds shear stress and vortex structures were decreased, the intensity of the jet like flow were significantly attenuated for the gap ratios of G/D=0.25, 0.50 and 0.75.

Investigation of Streaming Flow Patterns in a Thermoacoustic Device Using PIV

2010 ◽  
Author(s):  
Hadi Babaei ◽  
Kamran Siddiqui
Keyword(s):  
Particle Image ◽  
Velocity Fields ◽  
Two Dimensional ◽  
Cold Side ◽  
Velocity Magnitude ◽  
Piv Technique ◽  
Image Velocimetry ◽  
Streaming Velocity ◽  
The Difference ◽  
Streaming Flow

We report on an experimental study conducted to study the streaming velocity fields in the vicinity of the stack in a thermoacoustic device. Synchronized Particle Image Velocimetry (PIV) technique was used to measure the two-dimensional streaming velocity fields. The streaming velocity fields were measured at both sides of the porous stack over a range of pressure amplitudes (drive ratios). The results show that the streaming flow structure is significantly different on hot and cold sides of the stack. The hot side of the stack experienced higher magnitudes and higher spatial variability of the streaming velocities compared to the cold side. The difference in the velocity magnitude between the hot and cold sides of the stack showed a significant increase with an increase in the drive ratio.

Fuel Composition Effects on the Velocity Field in a Lean Premixed Swirl-Stabilized Combustor

2003 ◽  
Author(s):  
Donald M. Wicksall ◽  
Ajay K. Agrawal ◽  
Robert W. Schefer ◽  
Jay O. Keller
Keyword(s):  
Velocity Field ◽  
Atmospheric Pressure ◽  
Particle Image ◽  
Velocity Fields ◽  
Fuel Composition ◽  
Composition Effects ◽  
Piv Technique ◽  
Image Velocimetry ◽  
Lean Premixed ◽  
Recirculation Zones

Fuel composition effects on the flow-field of a lean premixed swirl-stabilized burner were studied. Methane (CH4) was enriched with hydrogen (H2) to vary the fuel composition. The burner inlet had 28-degree swirl vanes located in the annulus around a centerbody. Combustion occurred in an air-cooled quartz chamber at atmospheric pressure. The measurements were obtained, using the particle image velocimetry (PIV) technique, which allowed the 2-D velocity and vorticity fields to be examined for different fuels. The average velocity field was significantly altered, including the shape of the central and corner recirculation zones in the H2 enriched flames. The instantaneous velocity fields showed corresponding differences as well. The length scales and vorticity levels of the time-averaged velocity field differed from those for the instantaneous fields, indicating the importance of temporally resolved measurements.

Hydrodynamic Forces and DPIV on a Towed Pitching Foil

2014 ◽  
Author(s):  
R. Fernandez-Prats ◽  
F. J. Huera-Huarte
Keyword(s):  
Particle Image ◽  
Velocity Fields ◽  
Stepper Motor ◽  
Flow Structures ◽  
Caudal Peduncle ◽  
Hydrodynamic Loads ◽  
Caudal Fin ◽  
Image Velocimetry ◽  
Different Types ◽  
Set Up

More than 90% of the thrust generated by thunniform swimmers is known to be produced by the oscillation of their caudal fin, and the rest by their caudal peduncle. We have designed an experiment in which we can mimic, in a simplified manner, the kinematics of swimmers that mainly use their caudal fin for propulsion. The set-up consists of a rectangular foil attached to a shaft that is controlled by a stepper motor, and the whole assembly can be towed in still water at different controllable speeds. With this system we can study the effect of different types of pitching on the hydrodynamic loads and the performance of the propulsion system. By changing the type of foil, the effects of the flexibility in the propulsion can also be analysed. Hydrodynamic loads were measured with a 6-axes balance, and the flow structures were investigated using a Digital Particle Image Velocimetry (DPIV). Loads and DPIV velocity fields were acquired synchronously.

scholarly journals The effect of hand posture on swimming efficiency

2021 ◽  
Vol 62 (12) ◽  
Author(s):  
Joris van den Berg ◽  
Rens Bazuin ◽  
Constantin Jux ◽  
Andrea Sciacchitano ◽  
Jerry Westerweel ◽  
...  
Keyword(s):  
Particle Image ◽  
Real Life ◽  
Stationary Flow ◽  
Velocity Fields ◽  
Flow Structures ◽  
Hand Posture ◽  
Front Crawl ◽  
Propulsion Efficiency ◽  
Image Velocimetry ◽  
Swimming Efficiency

Abstract Our quest is for the thumb and finger positions that maximize drag in front crawl swimming and thus maximize propulsion efficiency. We focus on drag in a stationary flow. Swimming is in water, but using Reynolds similarity the drag experiments are done in a wind tunnel. We measure the forces on real-life models of a forearm with hands, flexing the thumb and fingers in various positions. We study the influence on drag of cupping the hand and flexing the thumb. We find that cupping the hand is detrimental for drag. Swimming is most efficient with a flat hand. Flexing the thumb has a small effect on the drag, such that the drag is largest for the opened (abducted) thumb. Flow structures around the hand are visualized using robotic volumetric particle image velocimetry. From the time-averaged velocity fields we reconstruct the pressure distribution on the hand. These pressures are compared to the result of a direct measurement. The reached accuracy of $$\approx$$ ≈  10% does not yet suffice to reproduce the small drag differences between the hand postures. Graphical Abstract

scholarly journals THERMOCAPILLARY MONITORING USING PARTICLE IMAGE VELOCIMETRY ASSOCIATED WITH DYNAMIC LASER SPECKLE

2020 ◽  
Vol 5 (1) ◽  
pp. 1-5
Author(s):  
Ellem Waleska Nascimento da Fonseca Contado ◽  
Roberto Alves Braga Júnior ◽  
Henrique Coelho Barbosa ◽  
Renan Oliveira Reis ◽  
Radhakrishna Prabhu
Keyword(s):  
Particle Image Velocimetry ◽  
Laser Beam ◽  
Velocity Distribution ◽  
Particle Image ◽  
Physical Phenomenon ◽  
Flow Analysis ◽  
Ccd Camera ◽  
Laser Speckle ◽  
Piv Technique ◽  
Image Velocimetry

Thermocapillarity is a physical phenomenon used in many industrial processes, mainly in the field of miniaturization. Thermocapillary forces are the base of thermocapillary pumping (TCP), in which a drop of liquid moves through a microchannel or flat surface after temperature gradient occurs. The objective of this work was to study the thermocapillary convection during pumping without inserting external particles, monitored by the Particle Image Velocimetry (PIV) technique. The experiment consisted of a Pasteur tube containing a yellow fluorescein solution (0.02, 0.04, 0.06, 0.08, and 0.1 Molar), illuminated by a laser beam of 545 nm, 40 mW. After 2 minutes of illumination, the thermocapillary movement occurred at a distance of 0.05 mm below the meniscus when using a laser beam of 545 nm, 3 mW. The images were captured by a charge-coupled device (CCD) camera and processed using the PIV technique. The results showed an internal conversion capacity between the intersystem crossing, vibrational, and relaxation phenomena, also demonstrating the potential for applying the proposed approach. The images presented velocity distribution caused by thermocapillarity. The PIV was a useful tool for convective flow analysis if connected to appropriate image processing and enhancement techniques. In conclusion, the research showed the images with velocity distribution caused by thermocapillarity.

PIV MEASUREMENTS AND NUMERICAL VALIDATION OF END-TO-SIDE ANASTOMOSIS

2010 ◽  
Vol 10 (01) ◽  
pp. 123-138 ◽  
Author(s):  
AMAL OWIDA ◽  
HUNG DO ◽  
WILLIAM YANG ◽  
YOS S. MORSI
Keyword(s):  
Particle Image ◽  
Three Dimensional ◽  
Quantitative Information ◽  
Velocity Fields ◽  
Flow Conditions ◽  
Ansys Software ◽  
Piv Measurements ◽  
Piv Technique ◽  
Image Velocimetry ◽  
Glass Model

In this article, particle image velocimetry (PIV) technique was used to determine the instantaneous velocity fields inside a model of end-to-side anastomosis under various physiological flow conditions. Using ANSYS software, a three-dimensional (3D) computational model at the peak systolic blood flow was simulated. The numerical and experimental results were presented and discussed in terms of velocity fields at various locations along the graft and the host artery. The numerical results were then compared with the experimental data and a large difference was found, which was attributed to the imperfection of manufacturing the glass model and measurements error associated with PIV. The findings indicated in general that the analysis at peak systole, steady flow could help in providing essential quantitative information of the hemodynamics in anastomotic artery.

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