The statistics of power injected in a closed turbulent flow: Constant torque forcing versus constant velocity forcing

Jean Hugues Titon; Olivier Cadot

doi:10.1063/1.1539856

On the relationship of the injected power between constant torque forcing and constant velocity forcing of fully turbulent flow

Physics of Fluids ◽

10.1063/1.1714666 ◽

2004 ◽

Vol 16 (6) ◽

pp. 2140-2141 ◽

Cited By ~ 5

Author(s):

Olivier Cadot ◽

Jean Hugues Titon

Keyword(s):

Turbulent Flow ◽

Constant Velocity ◽

Constant Torque ◽

Relationship Of ◽

The Relationship

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An Experimental Investigation of the Dynamic Behavior of the Spatial RSSR Crank and Rocker Mechanism With an Asymmetrical Coupler

Journal of Engineering for Industry ◽

10.1115/1.3439091 ◽

1976 ◽

Vol 98 (4) ◽

pp. 1231-1236

Author(s):

W. S. Begg ◽

J. R. Ellis

Keyword(s):

Experimental Investigation ◽

Dynamic Behavior ◽

Constant Velocity ◽

Center Line ◽

Constant Torque ◽

Input And Output ◽

Euler Approach ◽

Force Components ◽

Dynamic Investigation ◽

Velocity Input

An experimental RSSR crank and rocker mechanism has been devised and manufactured to facilitate the dynamic investigation of the input and output torques present, the force components acting in the link members and at the joints of the machine under various loading conditions, for a number of different configurations. The behavior of the so-called redundant or passive degree of freedom is also investigated by means of a coupler (floating link) having its center of gravity offset from the center line of the spherical joints at its ends. Experimental observations are made for the constant torque and constant velocity input conditions, as obtained in a practical mechanism, for the various machine configurations and loading arrangements. An analytical model is developed using the classical Newton-Euler approach and an example of the correlation of the analytical and experimental results is given.

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Multibody and Electromechanical Modelling in Dynamic Balancing of Mechanisms for Mechanical and Electromechanical Systems

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.147-149.339 ◽

2009 ◽

Vol 147-149 ◽

pp. 339-344

Author(s):

Krzysztof Lipiński

Keyword(s):

Numerical Modelling ◽

Numerical Optimization ◽

Constant Velocity ◽

Dc Motor ◽

Electromechanical System ◽

Dynamic Balancing ◽

Electromechanical Systems ◽

Constant Torque ◽

Simultaneous Elimination

The paper focuses on dynamics of an electromechanical system composed of a DC motor and a planar four-bar mechanism. Minimization of mechanism/frame interactions is considered. Simultaneous elimination of frame shaking forces and torques is requested. The employed balancing method is counterweights allocation. Their parameters are found with a numerical modelling and a numerical optimization. They depend on shape of the mechanism’s velocity. Three alternative drives are tested in the paper: constant velocity drive; constant torque drive; and DC motor. The optimal counterweight’s parameters are derived for all these drives. Obtained results approved necessity of precise electromechanical modelling.

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The Reduced Drag of Polymer Solutions in Turbulent and Transient Laminar Shear Flows

Journal of Fluids Engineering ◽

10.1115/1.3446953 ◽

1973 ◽

Vol 95 (1) ◽

pp. 23-28 ◽

Cited By ~ 4

Author(s):

R. J. Hansen

Keyword(s):

Turbulent Flow ◽

Polymer Solution ◽

Constant Velocity ◽

Random Function ◽

Polymer Solutions ◽

Unusual Behavior ◽

Infinite Extent ◽

The Mean ◽

Flow Drag ◽

Laminar Shear

The laminar flow of a polymer solution near a flat plate of infinite extent is investigated theoretically for three cases: (a) the plate is impulsively started and moves in its own plane with a constant velocity; (b) it executes linear harmonic oscillations in its own plane; (c) its motion in this plane is a random function of time. In each case the mean square value of the drag exerted on the plate by the polymer solution is predicted to be less than that by a Newtonian fluid of the same viscosity and density. The results are combined with a simple model for the turbulent boundary layer, and a number of experimentally observed characteristics of the turbulent flow drag reduction phenomenon are predicted. The merits of this transient shear explanation for the unusual behavior of polymer solutions in turbulent flow are compared to those of previously offered hypotheses.

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Numerical Analysis of Agitated Flow Field of Submersible Mixer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.139-141.2681 ◽

2010 ◽

Vol 139-141 ◽

pp. 2681-2684

Author(s):

Wei Xing Xu ◽

Shou Qi Yuan

Keyword(s):

Numerical Analysis ◽

Flow Field ◽

Turbulent Flow ◽

Coordinate System ◽

Constant Velocity ◽

Volume Flow ◽

The Body ◽

Design Parameters ◽

Turbulent Model ◽

Tip Radius

The flow formulation was founded as console formulation, and with the body-fitted coordinate system and standard k - ε turbulent model, the numerical analysis of the internal 3-D incompressible turbulent flow of the agitated flow field was carried out by CFD software Fluent. The results showed that: the mixer impeller produced vortex jet flow, the constant velocity lines advanced as ellipse, the velocity along the centerline are larger than others, and utilized volume flow to transport the liquid. And, by changing some design parameters of mixer impeller, we can compare and analyze the numerical analysis results and find that: for the same impeller diameter, the mixer impeller whose hub/tip radius ratio is smaller has larger advancing speed in the agitated flow field, and the advancing speed is more evenly distributed, so the overall effect is better. Therefore, we should select the hub diameter of the submersible mixer properly.

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Record Wear Studies by Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101578 ◽

1968 ◽

Vol 26 ◽

pp. 364-365

Author(s):

M.D. Coutts ◽

E.R. Levin ◽

J.G. Woodward

Keyword(s):

Electron Microscopy ◽

Constant Velocity ◽

Peak Velocity ◽

Great Depth ◽

Depth Of Focus ◽

Sweep Frequency ◽

Transmission Electron ◽

Test Record ◽

Lateral Mode ◽

Scanning Electron

While record grooves have been studied by transmission electron microscopy with replica techniques, and by optical microscopy, the former are cumbersome and restricted and the latter limited by lack of depth of focus and resolution at higher magnification. With its great depth of focus and ease in specimen manipulation, the scanning electron microscope is admirably suited for record wear studies.A special RCA sweep frequency test record was used with both lateral and vertical modulation bands. The signal is a repetitive, constant-velocity sweep from 2 to 20 kHz having a duration and repetitive rate of approximately 0.1 sec. and a peak velocity of 5.5 cm/s.A series of different pickups and numbers of plays were used on vinyl records. One centimeter discs were then cut out, mounted and coated with 200 Å of gold to prevent charging during examination. Wear studies were made by taking micrographs of record grooves having 1, 10 and 50 plays with each stylus and comparing with typical “no-play” grooves. Fig. 1 shows unplayed grooves in a vinyl pressing with sweep-frequency modulation in the lateral mode.

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