Comparison of Experimental and Simulated Grain Flows

Fully three-dimensional computer simulations of identical spheres flowing in an inclined glass-walled channel only slightly wider than a particle diameter successfully reproduce profiles of mean velocity, bulk density, and particle rotations as well as profiles of fluctuating quantities measured from high-speed motion pictures of physical experiments. All simulation parameters are measured experimentally. Both full simulations of the geometry of the physical experiments and simulations using periodic boundary conditions in the downchute direction are used to gather micromechanical information. For these collision-dominated flows, quantitative predictions of the simulations are relatively insensitive to details of the particle-interaction model and particularly the particle stiffness, but are relatively sensitive to extraneous fluid drag forces and the chute geometry.

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Saturated Ground Vibration Analysis Based on a Three-Dimensional Coupled Train-Track-Soil Interaction Model

Applied Sciences ◽

10.3390/app9234991 ◽

2019 ◽

Vol 9 (23) ◽

pp. 4991 ◽

Cited By ~ 4

Author(s):

Li ◽

Su ◽

Kaewunruen

Keyword(s):

High Speed ◽

Three Dimensional ◽

Interaction Model ◽

Ground Vibration ◽

Field Measurements ◽

Soil Conditions ◽

Layered Soils ◽

Train Track ◽

Dynamic Interactions ◽

Vibration Responses

A novel three-dimensional (3D) coupled train-track-soil interaction model is developed based on the multi-body simulation (MBS) principle and finite element modeling (FEM) theory using LS-DYNA. The novel model is capable of determining the highspeed effects of trains on track and foundation. The soils in this model are treated as saturated media. The wheel-rail dynamic interactions under the track irregularity are developed based on the Hertz contact theory. This model was validated by comparing its numerical results with experimental results obtained from field measurements and a good agreement was established. The one-layered saturated soil model is firstly developed to investigate the vibration responses of pore water pressures, effective and total stresses, and displacements of soils under different train speeds and soil moduli. The multi-layered soils with and without piles are then developed to highlight the influences of multi-layered soils and piles on the ground vibration responses. The effects of water on the train-track dynamic interactions are also presented. The original insight from this study provides a new and better understanding into saturated ground vibration responses in high-speed railway systems using slab tracks in practice. This insight will help track engineers to inspect, maintain, and improve soil conditions effectively, resulting in a seamless railway operation.

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Measurement of Three-Dimensional Particle Distribution by Tomographic Digital Holography

Volume 2A: Fora, Part 2 ◽

10.1115/ajkfluids2015-19199 ◽

2015 ◽

Author(s):

Shunsuke Tani ◽

Yohsuke Tanaka ◽

Shigeru Murata

Keyword(s):

Pattern Matching ◽

High Speed ◽

Digital Holography ◽

Particle Distribution ◽

Three Dimensional ◽

Particle Diameter ◽

Average Diameter ◽

Calibration Device ◽

Calibration Accuracy ◽

Static Flow

This paper presents a measurement of three-dimensional particle distribution by tomographic digital holography. Holographic patterns of particles (particle Reynolds number Rep=0.79, average diameter dp=73.5 μm) settling in a static flow were recorded by two high speed cameras orthogonal to each other. Cameras were calibrated by a proposed method using a calibration device and a pattern matching. The calibration accuracy of the method is within 0.34 times of particle diameter.

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CFD SIMULATION AND CHARACTERIZATION OF A DEVICE FOR POWDERED PHARMACEUTICALS AND BIOLOGICALS DELIVERY

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519406001923 ◽

2006 ◽

Vol 06 (03) ◽

pp. 285-297

Author(s):

FANG LIU ◽

WEI HE ◽

CHUNLI CAO ◽

YI LIU

Keyword(s):

High Speed ◽

Cfd Simulation ◽

Biological Effects ◽

Particle Interaction ◽

Mean Velocity ◽

Micro Particles ◽

Venturi Effect ◽

Underlying Principle ◽

Wide Range

Advances in molecular biology have produced a wide range of protein and peptide-based drugs. Equally, it is required to explore various technologies and capabilities to deliver those drugs. A unique medical device, the hand-held biolistics, is developed for powdered pharmaceuticals/biologicals transdermal delivery. The underlying principle is to accelerate micro-particles by means of a high-speed helium gas to an appropriate momentum to penetrate the outer layer of the skin to elicit desirable pharmaceutical/biological effects. The novelty of this hand-held biolistics is using the venturi effect to entrain micron-sized protein and peptide drugs into an established quasi-steady transonic jet flow and accelerate them toward the target. In this paper, computational fluid dynamics is utilized to characterize prototype biolistic system. The key features of gas dynamics and gas–particle interaction are presented. The overall capability of the biolistic delivery system is discussed and demonstrated. The statistical analyses show that the particles have achieved a mean velocity of 628 m/s as representatives of extracellular vaccine delivery applications.

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Flow Investigation Around a V-Sector Ball Valve

Journal of Fluids Engineering ◽

10.1115/1.1385831 ◽

2001 ◽

Vol 123 (3) ◽

pp. 662-671 ◽

Cited By ~ 12

Author(s):

P. Merati ◽

M. J. Macelt ◽

R. B. Erickson

Keyword(s):

High Speed ◽

Dynamic Pressure ◽

Three Dimensional ◽

Ball Valve ◽

Operating Conditions ◽

Mean Velocity ◽

Model Flow ◽

Flow Investigation ◽

And Behavior ◽

The Relationship

Experimental and computational methods were used to study the structure and behavior of the shedded vortices around a V-ball valve. Strouhal frequency for shedded vortices around the valve over a range of operating conditions and flow rates using water as the medium were measured. The information gathered in this study would help to predict at what operating conditions pipe ruptures might occur. A dynamic pressure transducer was used to determine the Strouhal frequency. LDV was used to measure the mean velocity and turbulence magnitudes. FLUENT was used to develop a two dimensional fluid dynamics model. Flow was visualized using high-speed video photography. A dominant large three-dimensional vortex downstream of the valve was detected. The centerline of this vortex is a shadow of the valve lip. A fifth degree polynomial describing the relationship between the Strouhal number and Reynolds number is obtained.

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Kinematic, aerodynamic and anatomical mechanisms in the slow, maneuvering flight of pigeons

Journal of Experimental Biology ◽

10.1242/jeb.201.5.655 ◽

1998 ◽

Vol 201 (5) ◽

pp. 655-672 ◽

Cited By ~ 14

Author(s):

D Warrick ◽

K P Dial

Keyword(s):

High Speed ◽

Neural Control ◽

Body Position ◽

Three Dimensional ◽

Bank Angle ◽

Drag Forces ◽

Maneuvering Flight ◽

Infrared Video ◽

Nearly Continuous ◽

Average Body

A high-speed (200 Hz) infrared video system was used in a three-dimensional analysis of pigeon wing and body kinematics to determine the aerodynamic and anatomical mechanisms they use to produce force asymmetries to effect a turn during slow (3 m s-1) flight. Contrary to our expectations, pigeons used downstroke velocity asymmetries, rather than angle of attack or surface area asymmetries, to produce the disparities in force needed for directional changes. To produce a bank, a velocity asymmetry is created early in the downstroke and, in the majority of cases, then reversed at the end of the same downstroke, thus arresting the rolling angular momentum. When the velocity asymmetry was not reversed at the end of downstroke, the arresting force asymmetry was produced during upstroke, with velocity asymmetries creating disparate drag forces on the wings. Rather than using subtle aerodynamic variables to produce subtle downstroke force asymmetries, pigeons constantly adjust their position using a series of large alternating and opposing forces during downstroke and upstroke. Thus, a pigeon creates a precise 'average' body position (e.g. bank angle) and flight path by producing a series of rapidly oscillating movements. Although the primary locomotor event (downstroke) is saltatory, maneuvering during slow flight should be considered as a product of nearly continuous, juxtaposed force generation throughout the wingbeat cycle. Further, viewing upstroke as more than stereotypical, symmetrical wing recovery alters the evolutionary and functional context of investigations into the musculoskeletal mechanisms and the associated neural control involved in this unique kinematic event.

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A Three-Dimensional Cinematographic Analysis of the Tennis Serve

International Journal of Sport Biomechanics ◽

10.1123/ijsb.2.4.260 ◽

1986 ◽

Vol 2 (4) ◽

pp. 260-271 ◽

Cited By ~ 73

Author(s):

Bruce Elliott ◽

Tony Marsh ◽

Brian Blanksby

Keyword(s):

High Speed ◽

Angular Displacement ◽

Three Dimensional ◽

Distal Segment ◽

High Speed Photography ◽

Mean Velocity ◽

Tennis Players ◽

Shoulder Joints ◽

Tennis Serve ◽

Male Subjects

Three dimensional (3-D) high-speed photography was used to record the tennis service actions of eight elite tennis players. The direct linear transformation (DLT) method was used for 3-D space reconstruction from 2-D images recorded from laterally placed cameras operating at 200fps. Seven of the eight subjects initially positioned their center of gravity toward the front foot during the stance phase. When the elbow reached 90° in the backswing, the knees of the eight subjects were at or near their maximum attained flexion, and the upper arm was an extension of a line joining both shoulder joints. A mean maximum vertical shoulder velocity of 1.7ms−1during the leg drive produced a force at the shoulder that was eccentric to the racket-limb, thus causing a downward rotation of this limb as measured by a mean velocity of the racket of −5.8ms−1down the back. This leg drive increased the angular displacement of the loop and therefore provided a greater distance over which the racket could be accelerated for impact. All subjects swung the racket up to the ball, and all but one hit the ball with the racket angled slightly backward (M= 93.9°). An effective summation of body segments was apparent because resultant linear velocities showed an increase as the more distal segment endpoint approached impact, although all subjects decelerated the racket immediately prior to impact. Mean resultant ball velocities of 34.4ms−1for the female subjects and 42.4ms−1for the male subjects were achieved.

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GLOBAL CLASSICAL SOLUTIONS FOR A COMPRESSIBLE FLUID-PARTICLE INTERACTION MODEL

Journal of Hyperbolic Differential Equations ◽

10.1142/s0219891613500197 ◽

2013 ◽

Vol 10 (03) ◽

pp. 537-562 ◽

Cited By ~ 15

Author(s):

MYEONGJU CHAE ◽

KYUNGKEUN KANG ◽

JIHOON LEE

Keyword(s):

Stokes Equations ◽

Particle Interaction ◽

Three Dimensional ◽

Interaction Model ◽

Planck Equation ◽

Navier Stokes ◽

Classical Solutions ◽

Navier Stokes Equations ◽

Global Classical Solutions ◽

System Coupling

We consider a system coupling the compressible Navier–Stokes equations to the Vlasov–Fokker–Planck equation on three-dimensional torus. The coupling arises from a drag force exerted by each other. We establish the existence of the global classical solutions close to an equilibrium, and further prove that the solutions converge to the equilibrium exponentially fast.

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High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168827 ◽

1994 ◽

Vol 52 ◽

pp. 218-219

Author(s):

Robert W. Mackin

Keyword(s):

Image Analysis ◽

High Speed ◽

Three Dimensional ◽

Image Data ◽

Ccd Camera ◽

Objective Lens ◽

Array Processor ◽

Vaginal Smears ◽

Low Contrast ◽

Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

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