Paper Presented at AIAA Conference (1/9/2006)
Dr. Sinha presented a paper entitled Sailplane Performance Improvement Using a Flexible Composite Surface Deturbulator at the 44th American Institute of Aeronautics and Astronautics Aerospace Sciences Meeting and Exhibit on January 9-12, 2006 in Reno, Nevada. This paper gives an in-depth look at Dr. Sinha's deturbulator research over the last three years using Standard Cirrus #60 as a test vehicle. The abstract reads:
A 5 to 20% increase in the glide ratio of a Standard Cirrus sailplane was observed across its flyable airspeed range by treating 60-100% of the span of the wing upper surface with a Flexible Composite Surface Deturbulator (FCSD) tape. The compliant surface layer of an appropriately positioned narrow FCSD strip undergoes sub-micron scale constrained mode flow-induced oscillations. This encourages the formation of a stable thin and long separation bubble like flow structure in non-zero pressure gradient boundary layers by delaying the breakdown of the shear layer separating the aforementioned bubble from the inviscid external flow. As a result, wind-tunnel tests showed the external flow is accelerated increasing lift, while skin friction is mitigated. This was confirmed by a reduction of the sailplane’s induced and parasitic drag components with extended span FCSD treatment. Furthermore, a parallel flight with a higher performance ASW-28 sailplane yielded results that corroborate these measurements.
For a PDF copy of the full paper, click AIAA 2006-447.
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