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.

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.

scholarly journals The non-Newtonian maxwell nanofluid flow between two parallel rotating disks under the effects of magnetic field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ali Ahmadian ◽  
Muhammad Bilal ◽  
Muhammad Altaf Khan ◽  
Muhammad Imran Asjad
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Brownian Motion ◽  
Flow Behavior ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Axial Direction ◽  
Rotating Disks ◽  
Physical Constraints ◽  
Fourth Order Method

Abstract The main feature of the present numerical model is to explore the behavior of Maxwell nanoliquid moving within two horizontal rotating disks. The disks are stretchable and subjected to a magnetic field in axial direction. The time dependent characteristics of thermal conductivity have been considered to scrutinize the heat transfer phenomena. The thermophoresis and Brownian motion features of nanoliquid are studied with Buongiorno model. The lower and upper disk's rotation for both the cases, same direction as well as opposite direction of rotation is investigated. The subsequent arrangement of the three dimensional Navier Stoke’s equations along with energy, mass and Maxwell equations are diminished to a dimensionless system of equations through the Von Karman’s similarity framework. The comparative numerical arrangement of modeled equations is further set up by built-in numerical scheme “boundary value solver” (Bvp4c) and Runge Kutta fourth order method (RK4). The various physical constraints, such as Prandtl number, thermal conductivity, magnetic field, thermal radiation, time relaxation, Brownian motion and thermophoresis parameters and their impact are presented and discussed briefly for velocity, temperature, concentration and magnetic strength profiles. In the present analysis, some vital characteristics such as Nusselt and Sherwood numbers are considered for physical and numerical investigation. The outcomes concluded that the disk stretching action opposing the flow behavior. With the increases of magnetic field parameter $$M$$ M the fluid velocity decreases, while improving its temperature. We show a good agreement of the present work by comparing with those published in literature.

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.

Locomotor forces on a swimming fish: three-dimensional vortex wake dynamics quantified using digital particle image velocimetry

1999 ◽  
Vol 202 (18) ◽  
pp. 2393-2412 ◽  
Author(s):  
E.G. Drucker ◽  
G.V. Lauder
Keyword(s):  
Particle Image Velocimetry ◽  
Swimming Speed ◽  
Particle Image ◽  
Fluid Velocity ◽  
Lepomis Macrochirus ◽  
Three Dimensional ◽  
Digital Particle Image Velocimetry ◽  
Force Balance ◽  
Vortex Rings ◽  
Image Velocimetry

Quantifying the locomotor forces experienced by swimming fishes represents a significant challenge because direct measurements of force applied to the aquatic medium are not feasible. However, using the technique of digital particle image velocimetry (DPIV), it is possible to quantify the effect of fish fins on water movement and hence to estimate momentum transfer from the animal to the fluid. We used DPIV to visualize water flow in the wake of the pectoral fins of bluegill sunfish (Lepomis macrochirus) swimming at speeds of 0.5-1.5 L s(−)(1), where L is total body length. Velocity fields quantified in three perpendicular planes in the wake of the fins allowed three-dimensional reconstruction of downstream vortex structures. At low swimming speed (0.5 L s(−)(1)), vorticity is shed by each fin during the downstroke and stroke reversal to generate discrete, roughly symmetrical, vortex rings of near-uniform circulation with a central jet of high-velocity flow. At and above the maximum sustainable labriform swimming speed of 1.0 L s(−)(1), additional vorticity appears on the upstroke, indicating the production of linked pairs of rings by each fin. Fluid velocity measured in the vicinity of the fin indicates that substantial spanwise flow during the downstroke may occur as vortex rings are formed. The forces exerted by the fins on the water in three dimensions were calculated from vortex ring orientation and momentum. Mean wake-derived thrust (11.1 mN) and lift (3.2 mN) forces produced by both fins per stride at 0.5 L s(−)(1) were found to match closely empirically determined counter-forces of body drag and weight. Medially directed reaction forces were unexpectedly large, averaging 125 % of the thrust force for each fin. Such large inward forces and a deep body that isolates left- and right-side vortex rings are predicted to aid maneuverability. The observed force balance indicates that DPIV can be used to measure accurately large-scale vorticity in the wake of swimming fishes and is therefore a valuable means of studying unsteady flows produced by animals moving through fluids.

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.

A Versatile Fully Submersible Stereo-PIV Probe for Tow Tank Applications

2003 ◽  
Author(s):  
Francisco Pereira ◽  
Tiziano Costa ◽  
Mario Felli ◽  
Guido Calcagno ◽  
Fabio Di Felice
Keyword(s):  
Particle Image ◽  
Water Channel ◽  
Three Dimensional ◽  
Stereoscopic Particle Image Velocimetry ◽  
Velocity Measurements ◽  
Piv Measurements ◽  
Circulating Water ◽  
Image Velocimetry ◽  
Out Of Plane ◽  
Yaw Angle

A unique, highly modular and flexible underwater system for stereoscopic particle image velocimetry (PIV) measurements has been designed, manufactured and tested. The instrument is intended for planar three-dimensional velocity measurements in large facilities such as water tow tanks and tunnels. The performance of the system is assessed in four major stereoscopic configurations. Errors under 2% for the in-plane components and 4% for the out-of-plane components are found. The system is tested in the INSEAN large circulating water channel where the measurement of the flow around a model ship oriented at a moderate yaw angle is performed and puts into evidence the main features of the flow.

scholarly journals Three-Dimensional Reconstruction of Evaporation-Induced Instabilities Using Volumetric Scanning Particle Image Velocimetry

Optics ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 52-70
Author(s):  
Mohammad Amin Kazemi ◽  
Janet A. W. Elliott ◽  
David S. Nobes
Keyword(s):  
Particle Image Velocimetry ◽  
Velocity Vector ◽  
Vector Fields ◽  
Particle Image ◽  
Laser Sheet ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Liquid Volume ◽  
Image Velocimetry ◽  
Out Of Plane

The three-dimensional (3D) flow below the interface of an evaporating liquid at a low pressure is visualized and quantified using scanning particle image velocimetry. The technique presented highlights the use of a single camera and a relatively fast moving laser sheet to image the flow for an application where using more than one camera is difficult. The technique allows collection of the full three-dimensional velocity vector map over the whole liquid volume. The out-of-plane component of the velocity has been determined using two different processing approaches: (i) deriving the full vector from a 3D cross-correlation of the particle volumes and (ii) applying the continuity equation to determine out-of-plane velocities from the calculated in-plane velocity vector fields. The results obtained from both methods showed good agreement with each other. The 3D velocity field reveals the existence of a torus shaped vortex below the evaporating meniscus that was induced by the exposure of the cold liquid to the warmer solid walls. The velocity data also shows that the maximum velocity occurs below the interface, not at the interface which highlights that the observed vortex is not driven by thermocapillary forces that usually govern the flow during evaporation at smaller scales.

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