Spectral analysis of vortex/free-surface interaction
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Authors
Hofert, Glenn D.
Subjects
Advisors
Sarpkaya, T.
Date of Issue
1994-06
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The unsteady flow phenomena resulting from the interaction of vorticity with a free surface has been investigated through the use of a three- color Laser Doppler-Velocimeter. The vorticity field was provided by a single tip vortex generated by an airfoil, placed in the test section of a recirculating water tunnel at a suitable angle of attack. All of the statistical quantities of flow such as turbulence and Reynolds stresses and in particular the spectrum of the fluctuations have been measured and analyzed. The results have shown that the free surface redistributes part or all of the normal turbulent kinetic energy into streamwise and spanwise components. Furthermore, the energy spectra have also shown that there exists an energy gradient on the free surface, on either side of the vertical passing through the original vortex. It is believed that the scars observed on the free surface are a consequence of the matching of the Bragg wave length with the wave length of the surface signatures within a particular spectrum
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
NA
Identifiers
NPS Report Number
Sponsors
Funder
NA
Format
63 p.;28 cm.