HIGHLIGHTS FROM THE BEST SPECIAL PROBLEM SUBMISSIONS
ME 303 FLUID DYNAMICS/ WESTPHAL/ WSU/ FALL 2000
To ME 303 Students for Fall 2000: Your final special problem submissions were FANTASTIC!
Here are some highlights from among the many outstanding submissions,
in no particular order:
- Mike Grega & Brian Severson worked together on the study of vortex shedding
around a cylinder in a flowing soap film sheet. They built their own soap film
apparatus, came up with an innovative
approach to measurement of the film flow speed, and were able to use video to discern
the vortex shedding. They report that the Strouhal number for vortex shedding in the
film agrees with that found in real (3-D) flow, but the appearance of the flow pattern
is different than that reported by others for 3-D flow. FANTASTIC!
- Ben Spence, Lisa Ellis, Alissa Nichols, and Andrew Dryden examined the ascent
velocity of bubbles in a liquid. Their experiments employed a video camera to enable
slow-motion analysis for determining the bubble's velocity and diameter. They found that,
although the bubbles they got were not small enough to get laminar flow, they did get
results in agreement with the published
drag data for rigid spheres at higher Reynolds numbers.
- Brian Fine examined the Law of the Wall controversy by evaluating how well
both of the proposed turbulent boundary layer
velocity functions fit 4 different measured velocity distributions. He
reports that the answer to "which is best?" depends on exactly how you make the comparison.
Brian's conclusions suggest that the current controversy will resist a clear-cut resolution!
- Kyle Hathaway, David Ball, and Matt Conrath measured the drag on two different models
of plank fences: the standard type (planks all on same side of rail), and the "good neighbor"
type, where the vertical planks are placed alternately on either side of the rail. Their
model employed a most sophisticated experimental approach: strain-gauge instrumented
poles! On their own initiative, they conducted
a study of the influence of wind direction too. They found that the good neighbor fence
experiences about 10% less drag for a perpendicular wind, but, interestingly,
a larger benefit when the
oncoming wind is not perpendicular to the fence line. That is a result you WON'T find
in a textbook!
- Wyatt Givens experimented with vents of varying diameter to find the optimum vent size
for most rapid draining of a 2 L bottle of water. Using a solid experimental design and
clear understanding gained from carefully examining the theory, he examined 4 different
vent configurations. He reported the fastest draining time of anyone (5.4 s), obtained
with a 5 mm vent tube.
- Scott Gallert studied the flow vs. depth over crest for a V-notch weir. His
well-designed experimental apparatus allowed weir plates to be easily changed out so
he could study the influence of weir plate thickness on the weir performance. He noted some
asymmetric flow for his thinnest weir plate, and saw a substantial difference in flow
vs. depth over crest for different thicknesses. Another insight you WON'T get from any
textbook!
- Peter Omel used a dual-chronometer test setup of his own conception
to obtain an estimate of the aerodynamic drag from the measured deceleration of a
hunting arrow in flight. The arrow left the bow at about 90 m/s! This was a cool idea!
- Travis Semmens & Kraig Williams used the drag build-up method to estimate the
drag on two different automobiles, then compared that estimate to wind tunnel measurements
made on scale models of their chosen automobiles. The measurements were remarkable close
to the predicted and published values.