NASA 1996 SBIR Phase I


PROPOSAL NUMBER : 96-1 01.09-9435

PROJECT TITLE : Non-intrusive skin-friction interferometer

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

A new fiber-optic device with non-moving parts capable of time-dependent single-point skin-friction measurements in subsonic/supersonic flow ranges and in separated/unseparated, steady/unsteady flow regimes is proposed. The device is low cost, very high resolution, interferometric (non-intrusive) and miniature (2.5"x2.25"x0.5"). The device needs calibration only once in its lifetime, and it can be used in cramped, highly vibrational environments due to its compact size and non-moving-parts design. The unique design of the device ensures that only a small portion of the device is in contact with high/low temperature environments which makes the device easily accommodating to different flow environments. The device generates linearly varying interference fringes perpendicular to the measurement surface within the sublayer of a boundary layer and uses the Doppler effect to measure one of the horizontal-to-surface velocity components within the sublayer. The linear variation of the velocity component within the sublayer and the linear variation of the fringes form a relation between the velocity component and the skin friction component on the surface due to Newtonžs principle.
POTENTIAL COMMERCIAL APPLICATIONS
The device will be used in applications where skin-friction drag on a surface is crucial in the design of a new product/device such as in the automotive, aircraft and maritime industries. The race car, speed boat, cycling industries and smaller industries such as surfing and skiing are also prime potential targets.

The device can be used in designing more efficient pumps, turbo machinery, jet engine, and internal combustion engine components where flow qualities including separation of the flow must be well known.

NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR
Dr. Semih Mehmet (tm)l‡men
Sensor Technology
1402 Ascot Lane
Blacksburg, VA 24060
NAME AND ADDRESS OF OFFEROR
Sensor Technology
1402 Ascot Lane
Blacksburg, VA 24060