Friday, October 20, 2006
2:00pm – 3:00pm
Professor
Steven Ceccio
Mechanical
Engineering
University
of Michigan
ÒScience
and Engineering of Friction Drag Reduction on ShipsÓ
Abstract:
For the past 5 years, our
group at the University of Michigan has examined a variety of drag reduction
methods that could be applied to ocean-going ships. Our effort has focused on micro-bubble drag reduction,
polymer drag reduction, air-layer drag reduction, and partial-cavity drag
reduction. We have conducted both laboratory-scale and large-scale experiments
to understand the underlying flow processes responsible for the presence (or
loss) of drag reduction, and to aid in the engineering evaluation of these
methods. Moreover, we have
partnered with a substantial group of researchers who have developed numerical
models of these complex flows.
Our high Reynolds number testing has been conducted on a large,
near-zero pressure gradient flat-plate test model, the HIPLATE. And, experiments were conducted in the
U. S. NavyÕs William B. Morgan Large Cavitation Channel, the largest
variable-pressure low-turbulence water tunnel in the world. We have examined boundary layer
flows of ReX greater than
200 million (Req
> 150,000) using a variety of instrumentation, including local skin friction
measurements, micro-PLIF and micro-PIV for polymeric flows, and optical and
electrical probes for the gas-liquid flows. In this talk I will present an overview of our findings
regarding each drag reduction methodology, along with an assessment of its
potential application to large-scale ships. I will also discuss our current tests on the roughened
HIPLATE, and our experiment planned for this Fall and Winter to study air-layer
and cavity drag reduction. This
research effort is supported by the Office of Naval Research and the Defense
Advanced Research Projects Agency.