Analysis of flow distribution from high-speed flow actuator using particle image velocimetry and digital speckle tomography

Velocity and density distributions of a high-speed and initial CO2 jet flow have been analyzed simultaneously by a developed three-dimensional digital speckle tomography and a particle image velocimetry (PIV). Three high-speed cameras have been used for the tomography and the PIV since a shape of a nozzle for the jet flow is asymmetric and the initial flow is fast and unsteady. The speckle movements between no flow and CO2 jet flow have been obtained by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields for the high-speed CO2 jet flow have been reconstructed from the deflection angles by the real-time tomography method, and the two-dimensional velocity fields have been calculated by the PIV method simultaneously.

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Analysis of Simultaneous Velocity and Density Distributions for High-Speed CO2 Flow Using Particle Image Velocimetry and Digital Speckle Tomography

Experimental Mechanics in Nano and Biotechnology - Key Engineering Materials ◽

10.4028/0-87849-415-4.55 ◽

2006 ◽

pp. 55-58

Author(s):

Han Seo Ko ◽

Yong Jae Kim ◽

Oh Chae Kwon ◽

Koji Okamoto

Keyword(s):

Particle Image Velocimetry ◽

High Speed ◽

Particle Image ◽

Density Distributions ◽

Image Velocimetry ◽

Digital Speckle

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Aerodynamics of manoeuvring flight in brown long-eared bats ( Plecotus auritus )

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0441 ◽

2018 ◽

Vol 15 (148) ◽

pp. 20180441 ◽

Cited By ~ 3

Author(s):

Per Henningsson ◽

Lasse Jakobsen ◽

Anders Hedenström

Keyword(s):

Particle Image Velocimetry ◽

Wind Tunnel ◽

High Speed ◽

Particle Image ◽

Future Studies ◽

Image Velocimetry ◽

Mechanistic Basis

In this study, we explicitly examine the aerodynamics of manoeuvring flight in animals. We studied brown long-eared bats flying in a wind tunnel while performing basic sideways manoeuvres. We used particle image velocimetry in combination with high-speed filming to link aerodynamics and kinematics to understand the mechanistic basis of manoeuvres. We predicted that the bats would primarily use the downstroke to generate the asymmetries for the manoeuvre since it has been shown previously that the majority of forces are generated during this phase of the wingbeat. We found instead that the bats more often used the upstroke than they used the downstroke for this. We also found that the bats used both drag/thrust-based and lift-based asymmetries to perform the manoeuvre and that they even frequently switch between these within the course of a manoeuvre. We conclude that the bats used three main modes: lift asymmetries during downstroke, thrust/drag asymmetries during downstroke and thrust/drag asymmetries during upstroke. For future studies, we hypothesize that lift asymmetries are used for fast turns and thrust/drag for slow turns and that the choice between up- and downstroke depends on the timing of when the bat needs to generate asymmetries.

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Velocity bias technique for particle image velocimetry measurements of high-speed flows

Applied Optics ◽

10.1364/ao.32.002159 ◽

1993 ◽

Vol 32 (12) ◽

pp. 2159 ◽

Cited By ~ 11

Author(s):

L M. Lourenco

Keyword(s):

Particle Image Velocimetry ◽

High Speed ◽

Particle Image ◽

Image Velocimetry ◽

High Speed Flows ◽

Velocity Bias

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Measurement of Air Flow Outside a Burning Cigarette during a Puff using Particle Image Velocimetry

Beiträge zur Tabakforschung International/Contributions to Tobacco Research ◽

10.2478/cttr-2013-0783 ◽

2004 ◽

Vol 21 (4) ◽

pp. 216-222

Author(s):

A Nagao ◽

K Miura ◽

S Kitao ◽

M Horio

Keyword(s):

Particle Image Velocimetry ◽

Particle Image ◽

Air Flow ◽

Maximum Velocity ◽

Flow Distribution ◽

Combustion Mechanism ◽

Air Flow Rate ◽

Tracer Particles ◽

Image Velocimetry ◽

Cigarette Paper

AbstractIn order to clarify the mechanism for the generation of cigarette smoke, the combustion mechanism of a burning cigarette during a puff was investigated by focusing on air transfer. In particular, the air flow distribution outside a burning cigarette was observed and related to the aerodynamic effects of the cigarette paper and the puffing rate. The air flow rate was measured by Particle Image Velocimetry (PIV), using olive oil droplets as the tracer particles. It was found that air does not flow into the tip of the burning cigarette and that the air flow was concentrated at the region -2 to 2 mm around the cigarette paper char-line. This behavior was independent of the cigarette paper basis weight. When the puffing rate was changed from 2.5 to 35 mL/s, the air flow was concentrated at a region close to the cigarette paper char-line and the maximum velocity around the cigarette paper char-line increased with the puffing rate.

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