scholarly journals Trolley Motion Control Based on S-shaped Velocity Profile for Quay Crane Cargo Oscillation Comparison

2017 ◽  
Vol 9 (3) ◽  
pp. 283-288
Author(s):  
Tomas Eglynas ◽  
Marijonas Bogdevičius ◽  
Arūnas Andziulis ◽  
Mindaugas Jusis
Keyword(s):  
Velocity Profile ◽  
Motion Control ◽  
Velocity Profiles ◽  
Minimum Time ◽  
Scaled Model ◽  
Crane Control ◽  
Quay Cranes ◽  
Profiling Techniques

Quay cranes are used to move containers from ship to store in minimum time so that the load reaches its destination without payload oscillation. During the operations, containers are suspended by cables and it’s free to swing by motion. This paper investigates the two different velocity profiling techniques used for quay crane control and cargo stabilization. A laboratory scaled model of a crane is used to experimentally research, where the trolley acceleration is used as input, for suppressing the container sway. The residual cargo oscillation problems using different velocity profiles are discussed.

scholarly journals The dam-break problem for concentrated suspensions of neutrally buoyant particles

2013 ◽  
Vol 724 ◽  
pp. 95-122 ◽  
Author(s):  
C. Ancey ◽  
N. Andreini ◽  
G. Epely-Chauvin
Keyword(s):  
Velocity Profile ◽  
Newtonian Fluid ◽  
Velocity Profiles ◽  
Lubrication Theory ◽  
Dam Break ◽  
Particle Migration ◽  
Flow Depth ◽  
Concentrated Suspensions ◽  
Front Position ◽  
Neutrally Buoyant

AbstractThis paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our experimental study are the simultaneous measurement of local flow properties far from the sidewalls (velocity profile and, with lower accuracy, particle concentration) and macroscopic features (front position, flow depth profile). To that end, the refractive index of the fluid was adapted to closely match that of the particles, enabling data acquisition up to particle volume fractions of 60 %. Particle migration resulted in the blunting of the velocity profile, in contrast to the parabolic profile observed in homogeneous Newtonian fluids. The experimental results were compared with predictions from lubrication theory and particle migration theory. For solids fractions as large as 45 %, the flow behaviour did not differ much from that of a homogeneous Newtonian fluid. More specifically, we observed that the velocity profiles were closely approximated by a parabolic form and there was little evidence of particle migration throughout the depth. For particle concentrations in the 52–56 % range, the flow depth and front position were fairly well predicted by lubrication theory, but taking a closer look at the velocity profiles revealed that particle migration had noticeable effects on the shape of the velocity profile (blunting), but had little impact on its strength, which explained why lubrication theory performed well. Particle migration theories (such as the shear-induced diffusion model) successfully captured the slow evolution of the velocity profiles. For particle concentrations in excess of 56 %, the macroscopic flow features were grossly predicted by lubrication theory (to within 20 % for the flow depth, 50 % for the front position). The flows seemed to reach a steady state, i.e. the shape of the velocity profile showed little time dependence.

scholarly journals New Infrared Diffuse Interstellar Bands in the Galactic Center and Elsewhere

2013 ◽  
Vol 9 (S297) ◽  
pp. 64-67
Author(s):  
T. R. Geballe
Keyword(s):  
Velocity Profile ◽  
Galactic Center ◽  
Velocity Profiles ◽  
Significant Fraction ◽  
Diffuse Interstellar Bands ◽  
The Galaxy ◽  
Band Spectra

AbstractThis paper updates the recent discovery of over a dozen new diffuse interstellar bands (DIBs), first in H-band spectra of stars in the Galactic center (GC) and toward stars in the Cygnus OB2 Association. The H-band DIBs, which currently number 15, are the longest wavelength DIBs reported to date and are the first found on sightlines toward the Galactic center. K-band (2.0-2.5 μm) spectra of the GC stars do not reveal additional DIBs. Comparison of the velocity profile of the strongest of the new DIBs in the sightline toward GCS3-2 (in the GC) with that toward Cygnus OB2 No. 9 and also with the broad velocity profiles of H3+ lines toward GCS3-2 confirm that a significant fraction of the diffuse material producing the DIB absorptions on sightlines to the GC is located within the central few hundred parsecs of the Galaxy.

Velocity Profiles of Turbulent Boundary Layers

1969 ◽  
Vol 73 (698) ◽  
pp. 143-147 ◽  
Author(s):  
M. K. Bull
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
Boundary Layers ◽  
Experimental Work ◽  
Constant Pressure ◽  
Velocity Profiles ◽  
Turbulent Boundary Layers ◽  
Boundary Layer Equations

Although a numerical solution of the turbulent boundary-layer equations has been achieved by Mellor and Gibson for equilibrium layers, there are many occasions on which it is desirable to have closed-form expressions representing the velocity profile. Probably the best known and most widely used representation of both equilibrium and non-equilibrium layers is that of Coles. However, when velocity profiles are examined in detail it becomes apparent that considerable care is necessary in applying Coles's formulation, and it seems to be worthwhile to draw attention to some of the errors and inconsistencies which may arise if care is not exercised. This will be done mainly by the consideration of experimental data. In the work on constant pressure layers, emphasis tends to fall heavily on the author's own data previously reported in ref. 1, because the details of the measurements are readily available; other experimental work is introduced where the required values can be obtained easily from the published papers.

Effect of Tapering on Pulsatile Flow Through a U-Tube Model of the Human Aortic Arch

2010 ◽  
Author(s):  
Masaru Sumida
Keyword(s):  
Velocity Profile ◽  
Pulsatile Flow ◽  
Velocity Profiles ◽  
Cross Sectional Area ◽  
Flow Rate Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
Turn Angle ◽  
Flow Through ◽  
The Cross

An experimental investigation of pulsatile flow through a tapered U-tube was performed to study the blood flow in the aorta. The experiments were carried out in a U-tube with a curvature radius ratio of 3.5 and a 50% reduction in the cross-sectional area from the entrance to the exit of the curved section. Velocity measurements were conducted by a laser Doppler velocimetry for a Womersley number of 10, a mean Dean number of 400 and a flow rate ratio of 1. The velocity profiles for pulsatile flow in the tapered U-tube were compared with the corresponding results in a U-tube having a uniform cross-sectional area. The striking effects of the tapering on the flow are exhibited in the axial velocity profiles in the section from the latter half of the bend to the downstream tangent immediately behind the bend exit. A depression in the velocity profile appears at a smaller turn angle Ω in the case of tapering, although the magnitude of the depression relative to the cross-sectional average velocity decreases. The value of β, which indicates the uniformity in the velocity profile over the cross section, decreases with increasing Ω, whereas it rapidly increases immediately behind the bend exit.

Flow Development in a Circular Duct With a Highly Distorted Inlet Condition

2007 ◽  
Author(s):  
Srinivas Badam ◽  
Jie Cui ◽  
Stephen Idem
Keyword(s):  
Numerical Model ◽  
Velocity Profile ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Pressure Gradients ◽  
Development Length ◽  
Circular Duct ◽  
Inlet Velocity ◽  
Inlet Condition ◽  
Flow Development

The development of air flow downstream of a stationary fan located in a circular duct was investigated. The objective of the research was to study the evolution of the velocity profiles and pressure gradients at various axial locations. The velocity profiles were measured at three different Reynolds numbers using a five-hole directional probe. Because the stationary fan caused the inlet velocity profile to be highly distorted, it was determined experimentally that the development length exceeded 20 duct diameters. Since this was greater than the length of the apparatus, a corresponding numerical model of the flow was generated using the commercial CFD software Fluent-6.1/6.2. The numerical model was validated against the experimental results. The hydrodynamic development length was therein determined numerically.

Different Predictions by the Minimum Variance and Minimum Torque-Change Models on the Skewness of Movement Velocity Profiles

2004 ◽  
Vol 16 (10) ◽  
pp. 2021-2040 ◽  
Author(s):  
Hirokazu Tanaka ◽  
Meihua Tai ◽  
Ning Qian
Keyword(s):  
Velocity Profile ◽  
Velocity Profiles ◽  
Minimum Variance ◽  
Movement Planning ◽  
System Stability ◽  
Movement Duration ◽  
Movement Velocity ◽  
Change Models ◽  
External Forces ◽  
Minimum Torque

We investigated the differences between two well-known optimization principles for understanding movement planning: the minimum variance (MV) model of Harris and Wolpert (1998) and the minimum torque change (MTC) model of Uno, Kawato, and Suzuki (1989). Both models accurately describe the properties of human reaching movements in ordinary situations (e.g., nearly straight paths and bell-shaped velocity profiles). However, we found that the two models can make very different predictions when external forces are applied or when the movement duration is increased. We considered a second-order linear system for the motor plant that has been used previously to simulate eye movements and single-joint arm movements and were able to derive analytical solutions based on the MV and MTC assumptions. With the linear plant, the MTC model predicts that the movement velocity profile should always be symmetrical, independent of the external forces and movement duration. In contrast, the MV model strongly depends on the movement duration and the system's degree of stability; the latter in turn depends on the total forces. The MV model thus predicts a skewed velocity profile under many circumstances. For example, it predicts that the peak location should be skewed toward the end of the movement when the movement duration is increased in the absence of any elastic force. It also predicts that with appropriate viscous and elastic forces applied to increase system stability, the velocity profile should be skewed toward the beginning of the movement. The velocity profiles predicted by the MV model can even show oscillations when the plant becomes highly oscillatory. Our analytical and simulation results suggest specific experiments for testing the validity of the two models.

Development of Pulse Ultrasonic Doppler Method for Flow Rate Measurements of Power Plant: Characteristics of Sound Pressure Distributions and Evaluation of the Hybrid Ultrasonic Flowmetering System Using TOF and UDM

2006 ◽  
Author(s):  
Hiroshige Kikura ◽  
Yuto Inoue ◽  
Masanori Aritomi ◽  
Michitsugu Mori
Keyword(s):  
Velocity Profile ◽  
Ultrasonic Velocity ◽  
Flow Rate ◽  
Time Of Flight ◽  
Velocity Profiles ◽  
Instantaneous Velocity ◽  
Rate Measurement ◽  
Flow Rate Measurement ◽  
Doppler Method ◽  
Flow Metering

A multi-beam pulse ultrasonic Doppler method has been developed for a new type of flow metering system. This new system is a hybrid of the time-of-flight type ultrasonic flowmeter and the ultrasonic velocity profile type flowmeter, having the advantages of these two types. Our final purpose is to apply the hybrid ultrasonic flow metering system to an accurate flow rate measurement of feed- or recirculation- water in nuclear power plants. The pulse ultrasonic Doppler method (UDM) has the capability to obtain instantaneous velocity profiles along an ultrasonic beam. The principle of the UDM flowmeter, which is one of the ultrasonic velocity profile type flowmeters, is based on the integration of an instantaneous velocity profile over a pipe diameter. The multi-beam system is expected to eliminate installation problems such as those of entry length, and also to follow transient flow rate more precisely by increasing the number of ultrasonic transducers. However, it needs reflectors for receiving ultrasonic Doppler signals. On the other hand, the time-of-flight (TOF) ultrasonic flow metering system does not need any reflector, but it needs profile factors (PFs) which depend on velocity profiles. PF is one of the important experimental coefficients for the accurate flow rate measurement. Therefore PFs must be corrected according to the changes in flow conditions. In the present study, we investigated to what degree the hybrid ultrasonic flow metering system can adjust the profile factors of the time-of-flight ultrasonic flow meters by using the multi-beam pulse ultrasonic Doppler method in metallic wall piping.

The Effects of Fins on the Intermediate Wake of a Submarine Model

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Juan M. Jiménez ◽  
Ryan T. Reynolds ◽  
Alexander J. Smits
Keyword(s):  
Shear Stress ◽  
Velocity Profile ◽  
Outer Region ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Turbulent Wake ◽  
Self Similar ◽  
Stress Profiles

Results are presented on the behavior of the turbulent wake behind a submarine model for a range of Reynolds numbers based on the model length between 0.49×106 and 1.8×106, for test locations between 3 and 9 diameters downstream of the stern. The shape of the model emulates an idealized submarine, and tests were performed with and without stern fins. In the absence of fins, the velocity profile in planes away from the influence of the sail rapidly becomes self-similar and is well described by a function of exponentials. The fins create defects in the velocity profiles in the outer region of the wake, while yielding higher values of turbulence at locations corresponding to the tips of the fins. Measurements conducted in planes away from the midline plane show that the velocity profiles remain self-similar, while the shear stress profiles clearly show the effects of the necklace vortices trailing from the base of the fins.

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