TY - JOUR
T1 - Measurement of the skin friction associated with turbulent flows in air and water using SAW devices
AU - Varadan, V. V.
AU - Roh, Y. R.
AU - Shankar, B.
AU - Varadan, V. K.
PY - 1990
Y1 - 1990
N2 - Shear stress measurement under dynamic loading by a low-frequency SAW (surface acoustic wave) sensor placed in a water channel with a fully developed turbulent flow and in an air flow generated by an electric fan is discussed. The SAW sensors used in the flow facility were fully calibrated for both shear stress and normal stress measurements, and hence, by measuring shifts in the oscillator frequency under flow conditions, actual values of the stress were obtained. The measured values show agreement with conventional intrusive measurement schemes. By using an appropriately sized SAW device and adjusting the frequency of operation, any spatial scale of the turbulence features can be characterized. For subsonic flows or for features changing at rates lower than the SAW oscillator frequencies, the temporal fluctuations can be measured in real time.
AB - Shear stress measurement under dynamic loading by a low-frequency SAW (surface acoustic wave) sensor placed in a water channel with a fully developed turbulent flow and in an air flow generated by an electric fan is discussed. The SAW sensors used in the flow facility were fully calibrated for both shear stress and normal stress measurements, and hence, by measuring shifts in the oscillator frequency under flow conditions, actual values of the stress were obtained. The measured values show agreement with conventional intrusive measurement schemes. By using an appropriately sized SAW device and adjusting the frequency of operation, any spatial scale of the turbulence features can be characterized. For subsonic flows or for features changing at rates lower than the SAW oscillator frequencies, the temporal fluctuations can be measured in real time.
UR - http://www.scopus.com/inward/record.url?scp=0025577641&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:0025577641
SN - 0090-5607
VL - 1
SP - 303
EP - 306
JO - Ultrasonics Symposium Proceedings
JF - Ultrasonics Symposium Proceedings
T2 - Proceedings of the IEEE 1990 Ultrasonics Symposium
Y2 - 4 December 1990 through 7 December 1990
ER -