Vibration and stability analysis of drivelines with self-excitation of non-constant velocity couplings

Instability at an Interface Between Oil and Flowing Water

Journal of Basic Engineering ◽

10.1115/1.3425580 ◽

1972 ◽

Vol 94 (4) ◽

pp. 874-878 ◽

Cited By ~ 5

Author(s):

W. T. Jones

Keyword(s):

Stability Analysis ◽

Thin Layer ◽

Diesel Fuel ◽

Constant Velocity ◽

Flowing Water ◽

Infinite Layer ◽

Droplet Entrainment

A linear, inviscid stability analysis is applied to the case of a relatively thin layer of stationary oil over a semi-infinite layer of water flowing at a constant velocity. Predictions of the velocity at which the interface becomes unstable and the effect of the oil depth on this velocity agree qualitatively with observations. Results can be applied to the problem of containing oil with mechanical booms. The model predicts initiation of oil loss by droplet separation from beneath the slick at low current velocities, for example, 0.39 to 0.53 fps for No. 2 diesel fuel depending on slick thickness. For practical purposes, earlier experiments have shown that this initial small oil loss by droplet entrainment can be tolerated up to a higher velocity of about 1.0 fps where substantial oil loss occurs.

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Stability of a stratified fluid with a vertically moving sidewall

Journal of Fluid Mechanics ◽

10.1017/s0022112008002164 ◽

2008 ◽

Vol 609 ◽

pp. 305-317 ◽

Cited By ~ 5

Author(s):

FRANÇOIS BLANCHETTE ◽

THOMAS PEACOCK ◽

RÉMI COUSIN

Keyword(s):

Boundary Layer ◽

Experimental Study ◽

Stability Analysis ◽

Constant Velocity ◽

Critical Value ◽

Quantitative Agreement ◽

Stratified Fluid ◽

Boundary Effects ◽

Layer Flow ◽

The Stability

We present the results of a combined theoretical and experimental study of the stability of a uniformly stratified fluid bounded by a sidewall moving vertically with constant velocity. This arrangement is perhaps the simplest in which boundary effects can drive instability and, potentially, layering in a stratified fluid. Our investigations reveal that for a given stratification and diffusivity of the stratifying agent, the sidewall boundary-layer flow becomes linearly unstable when the wall velocity exceeds a critical value. The onset of instability is clearly observed in the experiments, and there is good quantitative agreement with some predictions of the linear stability analysis.

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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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