Hydrodynamic drag force measurement of a functionalized surface exhibiting superhydrophobic properties

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Authors
Ley, James R.
Subjects
superhydrophobic
superhydrophilic
Femto-second laser surface processing
skin friction drag
Advisors
Kwon, Young W.
Date of Issue
2016-12
Date
Dec-16
Publisher
Monterey, California: Naval Postgraduate School
Language
Abstract
With superhydrophobic properties being extended to a variety of metallic substrates through the process of ablation due to femto-second laser surface processing (FLSP), it is important to understand the hydrodynamic benefits of such a material, as well as its resiliency. This research will focus on the skin friction drag effects of a superhydrophobic flat plate compared to an untreated flat plate of the same material and geometry. The resiliency of this material will also be tested through the use of an accelerated corrosion fog chamber using both treated and untreated aluminum samples. During complete submersion water channel testing, the velocity of the water was varied to yield a range of Reynolds numbers between 20,000 and 70,000 with respect to the test specimen. In this range, the FLSP treated plate showed consistently lower skin friction drag than that of the untreated plate. However, during the accelerated corrosion testing, the FLSP treated sample suffered from pitting corrosion at a rate faster than the untreated sample, effectively removing the surface treatment. While there are significant hydrodynamic benefits to this material, the elevated corrosion rates raise concerns about the resiliency of this surface treatment.
Type
Thesis
Description
Department
Mechanical and Aerospace Engineering (MAE)
Organization
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NPS Report Number
Sponsors
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Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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