The application of a nonintrusive laser-interferometer skin-friction meter, which measures skin friction with a remotely located laser interferometer that monitors the thickness change of a thin oil film, is extended both experimentally and theoretically to several complex wind-tunnel flows. These include two-dimensional seperated and reattached subsonic flows with large pressure and shear gradients, and two and three-dimensional supersonic flows at high Reynolds number, which include variable wall temperatures and cross-flows. In addition, it is found that the instrument can provide an accurate location of the mean reattachment length for separated flows. Results show that levels up to 120 N/sq m, or 40 times higher than previous tests, can be obtained, despite encountering some limits to the method for very high skin-friction levels. It is concluded that these results establish the utility of this instrument for measuring skin friction in a wide variety of flows of interest in aerodynamic testing.
[1]
L. Tanner,et al.
A study of the motion of oil films on surfaces in air flow, with application to the measurement of skin friction
,
1976
.
[2]
D. J. Monson,et al.
Skin Friction Measurements by a Dual-Laser-Beam Interferometer Technique
,
1981
.
[3]
Francis Arthur Jenkins,et al.
Fundamentals of Optics
,
1976
.
[4]
L H Tanner.
A skin friction meter, using the viscosity balance principle, suitable for use with flat or curved metal surfaces (based on thickness measurement)
,
1977
.
[5]
S. J. Kline,et al.
Describing Uncertainties in Single-Sample Experiments
,
1953
.
[6]
H. Tong,et al.
Computational procedure for evaluation of space shuttle TPS requirements. [Thermal Protection System
,
1974
.