Laminar flow control has been studied for several decades in an effort to achieve higher efficiencies
for aircraft. Successful implementation of laminar flow control technology on transport aircraft could
significantly reduce drag and increase operating efficiency and range. However, the crossflow instability
present on swept-wing boundary layers has been a chief hurdle in the design of laminar wings. The use of
spanwise-periodic discrete roughness elements (DREs) applied near the leading edge of a swept-wing
typical of a transport aircraft represents a promising technique able to control crossflow and delay
transition to accomplish the goal of increased laminar flow.
Recently, the Flight Research Laboratory at Texas A&M University conducted an extensive flight test
study using DREs on a swept-wing model at chord Reynolds numbers in the range of eight million. The
results of this study indicated DREs were able to double the laminar flow on the model, pushing transition
back to 60 percent chord. With the successful demonstration of DRE technology at these lower chord
Reynolds numbers, the next logical step is to extend the technology to higher Reynolds numbers in the
range of 15 to 20 million typical of smaller transport aircraft.
To conduct the flight tests at the higher Reynolds numbers, DREs will be placed on a wing glove
attached to the aircraft wing. However, a feasibility study was necessary before initiating the flight-testing.
First, a suitable aircraft able to achieve the Reynolds numbers and accommodate a wing glove was
identified. Next, a full CFD analysis of the aircraft was performed to determine any adverse effects on the
wing flow-field from the aircraft engines. This required an accurate CAD model of the selected aircraft.
Proper modeling techniques were needed to represent the effects of the aircraft engine. Once sufficient CFD results were obtained, they were used as guidance for the placement of the glove. The attainable
chord Reynolds numbers based on the recommendations for the wing glove placement then determined if
the selected aircraft was suitable for the flight-testing.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-05-7889 |
| Date | 2010 May 1900 |
| Creators | Neale, Tyler P. |
| Contributors | Reed, Helen |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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