Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Aeronautics and Astronautics

First Advisor

Rodney D. W. Bowersox, PhD


This study further developed and improved a miniature plastic cantilever floating element gauge for direct measurement of skin friction in shock tunnel tests. Gauge durability and usability were improved, and potential sources of error were quantified. A high frequency 30 kHz gauge (compared to the baseline 10 kHz gauge) was constructed by using an I-beam cantilever rather than a round beam. A directional gauge was developed and demonstrated by measuring the flowfield about a fin in the AFIT shock tunnel. The 10 kHz and 30 kHz gauges were used in two scramjet test sequences conducted at Mach 14 enthalpy (stagnation temperature of 6,000K); the first at the NASA Ames 16 inch shock tunnel with steady run time of 2 msec, the second at General Applied Science Laboratories' Hypulse facility with run time of 0.4 msec. A lower frequency gauge was used in Wright Laboratory Mach 6 wind tunnel tests. The cantilever gauge proved to be a rugged and accurate method of measuring skin friction. The I-beam gauge provides high frequency capability for facilities with very short run times. The directional gauge facilitates skin friction measurement where crossflow exists. The scramjet measurements provided engine designers with valuable efficiency data.

AFIT Designator


DTIC Accession Number