Particle Image Velocimetry (PIV) Measurements in Plunging Jets

2002 ◽  
Author(s):  
Kevin D. Nielsen ◽  
Larry J. Weber ◽  
Marian Muste
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Plunging Jets

Time-Resolved Particle Image Velocimetry (PIV) Measurements in a Radial Diffuser Pump

2009 ◽  
Author(s):  
Jianjun Feng ◽  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Time Resolved ◽  
Piv Measurements ◽  
Part Load ◽  
Channel Characteristic ◽  
Image Velocimetry ◽  
Pump Stage ◽  
Low Specific Speed ◽  
Load Conditions

The truly time-variant unsteady flow in a low specific speed radial diffuser pump stage has been investigated by time-resolved Particle Image Velocimetry (PIV) measurements. The measurements are conducted at the midspan of the blades for the design condition and also for some severe part-load conditions. The instantaneous flow fields among different impeller channels are analyzed and compared in detail, and more attention has been paid to flow separations at part-load conditions. The analysis of the measured results shows that the flow separations at two adjacent impeller channels are quite different at some part-load conditions. The separations generally exhibit a two-channel characteristic.

Wave-in-Deck Impact Loads in Relation With Wave Kinematics

2017 ◽  
Author(s):  
Jule Scharnke ◽  
Rene Lindeboom ◽  
Bulent Duz
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Impact Load ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Small Scale ◽  
Impact Loads ◽  
Piv Measurements ◽  
Wave Kinematics ◽  
Image Velocimetry

Breaking waves have been studied for many decades and are still of interest as these waves contribute significantly to the dynamics and loading of offshore structures. In current MARIN research this awareness has led to the setup of an experiment to determine the kinematics of breaking waves using Particle Image Velocimetry (PIV). The purpose of the measurement campaign is to determine the evolution of the kinematics of breaking focussed waves. In addition to the PIV measurements in waves, small scale wave-in-deck impact load measurements on a fixed deck box were carried out in the same wave conditions. To investigate the link between wave kinematics and wave-in-deck impact loads, simplified loading models for estimating horizontal deck impact loads were applied and compared to the measured impact loads. In this paper, the comparison of the model test data to estimated loads is presented.

scholarly journals Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine

2015 ◽  
Vol 1 (1) ◽  
pp. 345-348 ◽  
Author(s):  
Christoph Drobek ◽  
Robert Mau ◽  
Hermann Seitz
Keyword(s):  
Particle Image Velocimetry ◽  
Regenerative Medicine ◽  
Particle Image ◽  
Force Sensor ◽  
Water Jet ◽  
Fat Tissue ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Acting Force

AbstractParticle Image Velocimetry (PIV) measurements of a water-jet for water-assisted liposuction (WAL) are carried out to investigate the distribution of velocity and therefore momentum and acting force on the human sub-cutaneous fat tissue. These results shall validate CFD simulations and force sensor measurements of the water-jet and support the development of a new WAL device that is able to harvest low volumes of fat tissue for regenerative medicine even gentler than regular WAL devices.

scholarly journals Particle Image Velocimetry for in vitro characterization of Paravalvular Leakage of TAVR-sealing concepts

2021 ◽  
Vol 7 (2) ◽  
pp. 668-671
Author(s):  
Samuel Höing ◽  
Finja Borowski ◽  
Jan Oldenburg ◽  
Sabine Illner ◽  
Alper Öner ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Aortic Annulus ◽  
Piv Measurements ◽  
Paravalvular Leakage ◽  
Transcatheter Aortic Valve ◽  
Image Velocimetry

Abstract Paravalvular leakage (PVL), defined as the leakage between the aortic annulus and a transcatheter aortic valve replacement (TAVR), is verifiably associated with short- and long-term clinical outcome, especially with increased mortality. Therefore, with the ambition to reduce or even prevent PVL of next generation TAVR, it is necessary to extend the hemodynamic understanding of PVL. This study presents an in vitro flow measurement method to localize PVL during hydrodynamic characterization of TAVR and furthermore presents different design features, socalled outer skirt, to reduce PVL. Particle image velocimetry (PIV) measurements were performed for flow field assessment during hydrodynamic characterization of TAVR. Additionally, two different sealing concepts were developed to reduce PVL. The skirts were manufactured from polymeric-nonwoven and sued to pericardium-based TAVR-prototype. The prepared TAVR-prototypes were then deployed in a pathophysiological model of the aortic root with a calcification nodule of 2 mm according to ISO 5840:2021. To assess PVL, the flow field and the regurgitation volume was measured. The PIV measurements showed a clearly visible leakage jet between the TAVR-prototypes without skirt and the pathophysiological aortic annulus model. Jet velocities of up to 0.5 m/s were measured depending on presence or configuration of a PVL-preventing skirt. When implanted in the physiological annulus model without calcification nodule, PVL was hardly recognizable. The regurgitation volume of a TAVR-prototype without skirt at 5 l/min was 36.26±1.89 ml (n = 10). The developed and manufactured polymeric-nonwoven skirts reduced PVL from 37.67±1.17 ml to 18.36±1.8 ml (n = 10, TAVR-skirt-design1) and from 46.97±1.07 ml to 17.85±1.29 ml (n = 10, TAVR-skirt-design2) at 5 l/min. The localization of PVL during hydrodynamic characterization by means of PIV was successful. The sealing concepts developed in this work were very effective and led to a PVL-reduction of the tested TAVR prototypes of about 50% to 70%.

Experimental Investigation of an Acoustic Field Influence on a Development of the Plane Microjet by Particle Image Velocimetry (PIV)

2011 ◽  
Vol 6 (4) ◽  
pp. 42-50
Author(s):  
Yuriy Litvinenko ◽  
Maria Litvinenko ◽  
Mikhail Katasonov
Keyword(s):  
Particle Image Velocimetry ◽  
Acoustic Field ◽  
Vector Fields ◽  
Particle Image ◽  
Reynolds Numbers ◽  
Laser Flash ◽  
Piv Measurements ◽  
Low Reynolds Numbers ◽  
Image Velocimetry ◽  
Field Influence

An acoustic field influence on a development of the plane microjet at low Reynolds numbers were investigated experimentally employing Particle Image Velocimetry (PIV). Measurements were performed at synchronization of an acoustic signal phase with a laser flash. Instantaneous velocity fields of different cross- and longitudinal sections are occurred. Receptivity of the plane microjet to transversal acoustic disturbances is shown. PIV-images, correspond to them vector fields and vorticity fields are presented

Separation-Bubble-Transition Measurements on a Low-Re Airfoil Using Particle Image Velocimetry

2005 ◽  
Author(s):  
B. R. McAuliffe ◽  
M. I. Yaras
Keyword(s):  
Reynolds Number ◽  
Particle Image Velocimetry ◽  
Large Scale ◽  
Particle Image ◽  
Reverse Flow ◽  
Separation Bubble ◽  
Low Reynolds Number ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Low Reynolds

This paper presents experimental results on separation-bubble transition at low Reynolds number and low freestream turbulence, measured on an airfoil using particle image velocimetry (PIV). The two-dimensional PIV measurements have been performed over the suction surface of a low-Reynolds-number airfoil in a water tow-tank facility. Reynolds numbers, based on airfoil chord length and towing speed, of 40,000 and 65,000 have been examined at various angles of incidence, providing a range of streamwise pressure distributions and transitional separation-bubble geometries. The types of bubbles observed range from a short and thick bubble with separation near the leading edge of the airfoil, to a long and thin bubble with separation far downstream of the suction peak. The PIV measurements facilitate visualization of the vortex dynamics associated with separation-bubble transition. The growth of instability waves within the separated shear layer and eventual breakdown into turbulence is documented through the instantaneous vector fields. For all cases examined, large-scale vortex shedding and multiple reverse-flow zones are observed in the reattachment region. A technique for estimating the location of transition onset based on statistical turbulence quantities is presented, and comparisons are made to existing transition models.

PIV MEASUREMENTS OF DUAL SYNTHETIC JETS ACTUATOR DRIVEN BY ELECTRICAL FACTORS

2009 ◽  
Vol 23 (03) ◽  
pp. 417-420 ◽  
Author(s):  
ZHEN-BING LUO ◽  
ZHI-XUN XIA ◽  
BING LIU ◽  
DE-QUAN WANG ◽  
JIAN-XIN HU ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Driving Voltage ◽  
Transfer Phase ◽  
Piv Measurements ◽  
Synthetic Jet Actuator ◽  
Arbitrary Phase ◽  
Image Velocimetry

A dual synthetic jets actuator driven by different electrical factors was investigated using particle image velocimetry (PIV). A transfer-phase and sub-frequency technique was provided to capture the arbitrary phase of the dual synthetic jets, and a transfer-phase to equal technique was provided to determine the phase of the dual synthetic jets. The results show that both the amplitude and frequency of the electrical forcing voltages vastly affect the flow-field of the dual synthetic jets actuator. Both the forcing frequency and the driving voltage amplitudes contribute to the pressure difference and the area of the lower pressure, which determines the interactions of dual synthetic jets. The dual synthetic jet actuator exits a circumscription of electrical factors in which the actuator works efficiently.

PIV measurements in near-wake turbulent regions

2018 ◽  
Vol 32 (12n13) ◽  
pp. 1840026 ◽  
Author(s):  
Wei-Cheng Chen ◽  
Keh-Chin Chang
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Interrogation Window ◽  
Gray Level ◽  
Flow Properties ◽  
Near Wake ◽  
Piv Measurements ◽  
Optical Diagnostic ◽  
Piv Measurement ◽  
Image Velocimetry

Particle image velocimetry (PIV) is a non-intrusive optical diagnostic and must be made of the seedings (foreign particles) instead of the fluid itself. However, reliable PIV measurement of turbulence requires sufficient numbers of seeding falling in each interrogation window of image. A gray-level criterion is developed in this work to check the attainment of statistically stationary status of turbulent flow properties. It is suggested that the gray level of no less than 0.66 is used as the threshold for reliable PIV measurements in the present near-wake turbulent regions.

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