Holographic diffraction image velocimetry for measurement of three-dimensional velocity fields

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1201-1203
Author(s):  
James S. Slepicka ◽  
Soyoung S. Cha
Keyword(s):  
Three Dimensional ◽  
Velocity Fields ◽  
Diffraction Image ◽  
Image Velocimetry

Momentum Distribution in the Wake of a Trapezoidal Pitching Panel

2016 ◽  
Vol 50 (5) ◽  
pp. 9-23 ◽  
Author(s):  
Rajeev Kumar ◽  
Justin T. King ◽  
Melissa A. Green
Keyword(s):  
Strouhal Number ◽  
Particle Image ◽  
Three Dimensional ◽  
Velocity Fields ◽  
Stereoscopic Particle Image Velocimetry ◽  
Vortex Rings ◽  
Vortex Identification ◽  
Freestream Velocity ◽  
Image Velocimetry ◽  
Thrust Production

AbstractThe oscillation of bioinspired fin-like panels in a uniform freestream flow creates chains of vortex rings, including streamwise segments that induce significant three-dimensional effects. With increasing Strouhal number, this wake structure induces flow with increasing nondimensional momentum, defined relative to the freestream velocity, in the downstream direction. This increase in relative momentum with increasing Strouhal number is consistent with greater nondimensional thrust production, which has been shown previously in the literature. These results were obtained via stereoscopic particle image velocimetry water tunnel experiments at Strouhal numbers ranging from 0.17 to 0.56 downstream of a continuously pitching trapezoidal panel. Features of the wake dynamics including spanwise compression, transverse expansion, transverse wake splitting or bifurcation, and wake breakdown are elucidated through analyses of phase-averaged as well as time-averaged velocity fields, in addition to common vortex identification methods.

Instantaneous Measurement of Unsteady Three-Dimensional Velocity Fields With Photogrammetric PIV

2005 ◽  
Author(s):  
A. Schimpf ◽  
P. U. Thamsen
Keyword(s):  
Particle Image ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Industrial Applications ◽  
Velocity Fields ◽  
Dimensional Structure ◽  
Two Phase ◽  
Image Velocimetry ◽  
Flow Phenomena ◽  
Set Up

Knowledge about the three-dimensional structure of a velocity field is important for understanding multiple flow phenomena associated with off design operation of pumps and turbines, acoustic emissions or two phase flow to name but a few. The measurement of three-dimensional unsteady velocity fields in industrial applications requires a robust, easy to use and universal measurement system. Existing 3D-3C-Particle-Image Velocimetry (PIV) Systems like Holographic PIV (HPIV) or Defocus-PIV suffer from restrictions to the optical accessibility of the volume to be investigated and a sophisticated optical set up. Hence the objective of this paper is to present the advanced Photogrammetric PIV (PPIV), a robust and easy to use 3D-3C-PIV system applicable to flows in areas with limited optical accessibility like in housings of rotary machines.

Development of Three-Dimensional Streamline Image Velocimetry Using Superimposed Delaunay Triangulation and Geometrical Fitting

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Elishai Ezra ◽  
Eliezer Keinan ◽  
Alex Liberzon ◽  
Yaakov Nahmias
Keyword(s):  
Delaunay Triangulation ◽  
Flow Behavior ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Finite Size ◽  
Velocity Fields ◽  
Particle Tracing ◽  
Image Velocimetry ◽  
Out Of Plane ◽  
Algorithmic Approaches

Flow behavior in complex three-dimensional (3D) microscale domains is the key in the development of microcirculatory pathologies and the design of 3D microfluidics. While numerical simulations are common practice for the derivation of velocity fields in such domains, they are limited to known geometries. Current experimental methods such as micron-scale particle tracing comprise of intricate algorithmic approaches for the accurate tracing of numerous particles in a dense moving liquid suspension and are fundamentally limited in resolution to the finite size of the interrogated steps. Here, we introduce 3D streamlines image velocimetry (3D-SIV), a method to derive fluid velocity fields in arbitrary resolution for fully developed laminar flow in 3D geometries. Our approach utilizes 3D geometrical fitting and superimposed Delaunay triangulation to reconstruct streamtubes and to trace their volumetric changes. Our algorithm has applications in out-of-plane velocimetries, which we demonstrate in a 3D dilated curved geometry and in an ascending aorta. The 3D-SIV can be applied for high-resolution derivation of velocity fields in microcirculatory pathologies and to 3D microfluidic circuits, extending the potential of out-of-plane velocimetries to complex geometries and arbitrary resolution.

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.

scholarly journals Experimental Validation of Falling Liquid Film Models: Velocity Assumption and Velocity Field Comparison

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1205
Author(s):  
Ruiqi Wang ◽  
Riqiang Duan ◽  
Haijun Jia
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Experimental Validation ◽  
Particle Image ◽  
Velocity Fields ◽  
Number Range ◽  
Comparison Results ◽  
Image Velocimetry ◽  
Experimental Particle

This publication focuses on the experimental validation of film models by comparing constructed and experimental velocity fields based on model and elementary experimental data. The film experiment covers Kapitza numbers Ka = 278.8 and Ka = 4538.6, a Reynolds number range of 1.6–52, and disturbance frequencies of 0, 2, 5, and 7 Hz. Compared to previous publications, the applied methodology has boundary identification procedures that are more refined and provide additional adaptive particle image velocimetry (PIV) method access to synthetic particle images. The experimental method was validated with a comparison with experimental particle image velocimetry and planar laser induced fluorescence (PIV/PLIF) results, Nusselt’s theoretical prediction, and experimental particle tracking velocimetry (PTV) results of flat steady cases, and a good continuity equation reproduction of transient cases proves the method’s fidelity. The velocity fields are reconstructed based on different film flow model velocity profile assumptions such as experimental film thickness, flow rates, and their derivatives, providing a validation method of film model by comparison between reconstructed velocity experimental data and experimental velocity data. The comparison results show that the first-order weighted residual model (WRM) and regularized model (RM) are very similar, although they may fail to predict the velocity field in rapidly changing zones such as the front of the main hump and the first capillary wave troughs.

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