Double pulsed particle image velocimeter with directional resolution for complex flows

2004 ◽  
Vol 6 (2) ◽  
pp. 119-128 ◽  
Author(s):  
C. C. Landreth ◽  
R. J. Adrian ◽  
C. S. Yao
Keyword(s):  
Particle Image ◽  
Complex Flows ◽  
Particle Image Velocimeter

Lessons Learned From the Use of the Laser Doppler Velocimeter and the Particle Image Velocimeter for Water Flow Bounded by a Layer of Oil

2009 ◽  
Author(s):  
K. V. Wong ◽  
H. Samarajeewa ◽  
B. Itier
Keyword(s):  
Vector Fields ◽  
Open Channel ◽  
Particle Image ◽  
Open Channel Flow ◽  
Laser Doppler Velocimeter ◽  
Two Dimensional ◽  
Dimensional Vector ◽  
Tracer Particles ◽  
Oil Water ◽  
Particle Image Velocimeter

The objectives of this paper are to describe the learning of the use of the Laser Doppler Velocimeter (LDV) as well as the Particle Image Velocimeter (PIV), including the fine points in their usage for instructional purposes. The application is to measure the velocity distribution across a flow of water bounded by a layer of oil using lasers. The characteristics at the oil-water interface are very interesting. It would be significant to measure the velocity distributions around this region. Such a scenario occurs during oil spills and spills of oily chemical pollutants in the sea or open ocean. The LDV is a well established method for measuring both laminar and turbulent flows. In this method, tracer particles are used to assist in measuring velocity profiles. This method was pushed to the limit by measuring the velocity boundary layer in the open channel flow. The average free-stream velocity is measured by other conventional means as a check on the LDV measurements. The PIV method is an optical method used to obtain instantaneous velocity measurements and related properties in fluids. The fluid is seeded with tracer particles and it is the motion of these seeded particles that is used to calculate the velocity information of the flow being studied. The PIV produces two dimensional vector fields. The simple PIV system was pushed to the limit by using it to measure the velocities in the oil-water interface of an open channel flow bounded by oil on the surface. The major difference between the LDV and the PIV is that the LDV measurements are done at a point, whereas the PIV measures the velocity of a region. Furthermore, PIV produces two dimensional vector fields while the LDV produces only a velocity measurement.

Measuring turbulence in reversing flows by particle image velocimeter

1990 ◽  
Author(s):  
Ian Grant ◽  
A. Liu ◽  
E. H. Owens ◽  
Y. Y. Yan ◽  
G. H. Smith
Keyword(s):  
Particle Image ◽  
Particle Image Velocimeter

An Integrated Micron-Resolution Particle Image Velocimeter/Optical Tweezers (μPIVOT) for Microenvironment Investigations

2007 ◽  
Author(s):  
James K. Lingwood ◽  
Nathalie Ne`ve ◽  
Sean S. Kohles ◽  
Derek C. Tretheway
Keyword(s):  
Particle Image Velocimetry ◽  
Fluid Flow ◽  
Optical Tweezers ◽  
Particle Image ◽  
Optical Technique ◽  
Mechanical Environment ◽  
Image Velocimetry ◽  
Particle Hydrodynamics ◽  
Particle Image Velocimeter ◽  
The Individual

A novel instrument has been developed (μPIVOT) to manipulate and characterize the mechanical environment in and around microscale objects by integrating two laser-based techniques: micron-resolution particle image velocimetry (μPIV) and optical tweezers (OT). While the μPIVOT enables a new realm of microscale studies, it still maintains the individual capabilities of each optical technique. Ongoing investigations will provide a unique perspective towards understanding microscale phenomena including cell biomechanics, non-Newtonian fluid flow, and single particle or particle-particle hydrodynamics.

A directionally sensitive particle image velocimeter

1988 ◽  
Vol 21 (12) ◽  
pp. 1190-1195 ◽  
Author(s):  
I Grant ◽  
G H Smith ◽  
E H Owens
Keyword(s):  
Particle Image ◽  
Particle Image Velocimeter

scholarly journals Ultrasound PIV Uncertainty Quantification

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Rozhin Derakhshandeh ◽  
Sayantan Bhattacharya ◽  
Brett Meyers ◽  
Pavlos Vlachos
Keyword(s):  
Particle Image ◽  
Digital Signal ◽  
Working Fluid ◽  
Ultrasound Images ◽  
Complex Flows ◽  
Non Invasive ◽  
Uncertainty Sources ◽  
Image Shape ◽  
Non Gaussian ◽  
Particle Images

Ultrasound Particle image velocimetry (UPIV) is a non-invasive flow measurement technique where acousticopaque flow tracers are injected into a working fluid and ensonified to create ultrasound images. These images are processed using PIV cross-correlation based algorithms to measure the velocity field (Kim et al., 2004). UPIV is useful for opaque flows, primarily where complex flows exist, accordingly, it is used in many industrial and clinical research applications such as studying intracardiac flow (Crase et al., 2007). Furthermore, the measurement provides suitable temporal and spatial resolutions for improved diagnostic metrics. Mentioned applications and the sensitive diagnostic industrial and clinical decisions made based on these measurements intensifies the importance of characterizing the UPIV measurement accuracy and associated uncertainty. However, quantifying UPIV measurement uncertainty is non-trivial due to the complexity of possible uncertainty sources, their combination, and propagation through the measurement chain. The formation of a particle image by ultrasound significantly differs from optical imaging, introducing unique aspects to image quality that must be considered. Particle images are formed across several ultrasound scan lines, yielding an elliptical particle image shape. Furthermore, the particle’s reflected pressure wave is converted to a digital signal that undergoes signal modulation, and this process forms a non-Gaussian point spread function (PSF) along the scan line direction. Additionally, clusters of tracers produce a single, bright image intensity and speckle image pattern. Compared to conventional PIV images, UPIV incurs significantly higher image noise due to lack of filtration for the ultrasound reflection of the non-tracer obstacles.

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