Accession Number : ADA260482

Title :   Surface Acoustic Wave Sensors and Piezoelectric Actuators for Investigations of Transitional and Turbulent Flows.

Descriptive Note : Final technical rept.,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK

Personal Author(s) : Varadan, Vasundara V. ; Pauley, Wayne R. ; Varadan, Vijay K.

Report Date : MAY 1992

Pagination or Media Count : 37

Abstract : A dual SAW sensor attached in cantilever fashion to a free floating membrane flush mounted on a structure exposed to turbulent fluid flow are described. Shear stress on the membrane due to the flow conditions, deforms and bends the cantilever beam. The SAW devices are mounted such that one device is in compression and the other in tension. The cantilever arrangement magnifies the deformation of the SAW sensors by many orders of magnitude relative to the membrane. The SAW devices are attached to oscillator circuits and the change in frequency of the SAW oscillators due to the deformation can be accurately measured. The dual arrangement compensates changes in temperatures, electrical and mechanical noise and other changes and the difference in frequency measured by a mixer is directly related to the shear stress on the structure. Experiments conducted in a wind tunnel are described.

Descriptors :   *TURBULENT FLOW, *FLUID DYNAMICS, *SHEAR STRESSES, CANTILEVER BEAMS, COMPRESSION, DEFORMATION, FLUID FLOW, MEMBRANES, STRUCTURES, TEMPERATURE, TENSION, WIND TUNNELS, SURFACE ACOUSTIC WAVE DEVICES, ACOUSTIC DETECTORS, SKIN FRICTION, PRESSURE.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE