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Nonintrusive Method for Detecting Particle Movement Characteristics near Threshold Flow Conditions.
- Source :
-
Journal of Irrigation & Drainage Engineering . Nov2010, Vol. 136 Issue 11, p774-780. 7p. 2 Black and White Photographs, 4 Diagrams, 1 Chart, 5 Graphs. - Publication Year :
- 2010
-
Abstract
- Bed-load measurements comprise an important component in the development of reliable formulas, in an effort to obtain the necessary constitutive relations between the amount of transported material and flow parameters. The uncertainty of such measurements is rather well known, being much more pronounced at lower transport rates. This uncertainty stems from the multitude of factors affecting bed-load transport and the lack of available trustworthy measuring technologies. Predictions of the limiting case of nearly zero bed-load transport, typically reported in literature as threshold of motion or critical condition, are even more challenging. The purpose of this contribution is twofold. First, to examine the sensitivity of bed-load transport measurements at conditions moderately higher than critical, to the presence of a rather unobtrusive trap, designed through several iterations. Even under relatively simple laboratory flume channel and flow conditions, it proved difficult to measure the bed-load transport rate in a completely unbiased way. Second, to develop a methodology, together with the appropriate instrumentation, for determining the condition of incipient motion. The nonintrusive approach described here proved to be reliable in detecting even the slightest movements of a particle. At the same time, it demonstrates the complexity of the problem due to the highly fluctuating nature of turbulent flow. [ABSTRACT FROM AUTHOR]
- Subjects :
- *HYDRAULICS
*TURBULENCE
*BED load
*RIVERS
*FLUID mechanics
Subjects
Details
- Language :
- English
- ISSN :
- 07339437
- Volume :
- 136
- Issue :
- 11
- Database :
- Academic Search Index
- Journal :
- Journal of Irrigation & Drainage Engineering
- Publication Type :
- Academic Journal
- Accession number :
- 54473151
- Full Text :
- https://doi.org/10.1061/(ASCE)IR.1943-4774.0000252