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.