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Courtesy of Manhasset High School, Science Research Program, Manhasset,
New York
A unique program at Manhasset High School in New York allows students
to team up with local sponsors to perform independent research projects.
Paul Calluzzo and Pat Bennett are two students who have participated in
the program under the supervision of Peter Guastella. Their chosen project
was to develop a lab-scale flow visualization tool and to validate it
through the use of CFD. Experiments were performed using a dye wand and
an ultra-violet dye technique.
From left, Pat and Paul at the Intel ISEF in San Jose
To match the conditions (Reynolds number) typical of a full-sized moving
vehicle, the students realized that a lab-scale wind tunnel would require
extremely high speed flows. The use of water instead of air as the flow
medium would allow them to use more moderate flow speeds, so they began
investigating the purchase of a ready-made water tunnel. The cost was
prohibitive for their small budget, so they developed a series of plans
to build one. The first tunnel was constructed from painted wood, and
consisted of two large reservoirs flanking a straight test section where
visualization tests could be performed. The students later coated the
walls with fiberglass to make them smoother. They subsequently built a
new water tunnel using plexiglass. This material allowed for smooth interior
walls, better seals at the joints, and good visibility throughout the
unit. Two drains on the down-stream side gave rise to greater stability
in the test section and rapid cycling of the water through the system.
A simplified test vehicle was built, and visualization studies in the
tunnel using the dye wand and UV dye technique were compared to a CFD
study of the same flow. The students used GAMBIT to create a 2-D model
of the vehicle, and FLUENT to compute the turbulent flow field. After
obtaining a converged result, they extracted flow speeds from several
locations and charted locations where disturbances in the flow field prevailed.
The CFD results were compared to the dye wand and UV dye measurements.
While very good agreement with the dye wand data was obtained, measurements
made using the UV technique proved to be uninformative. The students concluded
that the UV technique was not well suited to this type of analysis, but
that a combination of dye wand measurements and CFD constitute a well-rounded
set of visualization tools.
Visualization of the vehicle using a dye wand (top) was compared to numerical
predictions made by FLUENT (bottom)
The students presented their work at the 2001 Fluent UGM in Manchester,
NH, where it was met with enthusiastic response from the audience. They
were the third place Grand Award winners at the INTEL International Science
and Engineering Fair held in San Jose, CA in May. In addition, they were
awarded two possible scholarships from engineering programs at Cornell
University and UC San Jose. They will continue their studies and research
next year. Both will return to Manhasset High School: Paul will be a senior
and Pat a junior. One of the projects planned for the water tunnel, which
will involve other students as well, is a study of bow wakes generated
by tankers with a variety of bulbous bow designs.
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