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Laser Doppler velocimetry momentum defect measurements of cable drag at low to moderate Reynolds numbers: feasibility study

Dimotakis, Paul E. (1977) Laser Doppler velocimetry momentum defect measurements of cable drag at low to moderate Reynolds numbers: feasibility study. California Institute of Technology , Pasadena, CA. (Unpublished) http://resolver.caltech.edu/CaltechAUTHORS:20101022-123953042

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Abstract

The problem of measuring cable drag coefficients at low to moderate Reynolds numbers (100 < Re < 30,000) is addressed and alternative methods of measurement are analyzed. The very low forces and pressures involved at the lower Reynolds numbers render conventional measurement methods less suitable candidates. Laser Doppler velocity measurements, however, of the momentum defect in the wake appear capable of yielding sufficient accuracy « ± 5%) in the determination of the drag coefficient. This conclusion assumes that a test facility can be utilized with a sufficiently uniform flow field, low turbulence level and a free stream velocity which either remains stable during the wake survey measurement time interval or can be monitored independently. Water and air appear as almost equal in their merits as working fluids. with water slightly preferable as not requiring scattering particle seeding.


Item Type:Report or Paper (Technical Report)
Additional Information:Naval Construction Battalion Center Contract No. N62583/77 - M - RS41
Funders:
Funding AgencyGrant Number
Naval Construction Battalion CenterN62583/77 - M - RS41
Record Number:CaltechAUTHORS:20101022-123953042
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20101022-123953042
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20485
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:22 Oct 2010 20:14
Last Modified:26 Dec 2012 12:32

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