The optical multichannel transducer array (OMTA) is a fiber
optic-based sensor designed to measure pressure profiles with high time
and spatial resolution for wind tunnel applications. The OMTA is an integration
of various state-of-the-art technologies and consists of two interchangeable
sensor array heads (10 channels, 32 channels) and the
associated fiber optics, a filter spectrometer with a 64-element detector
array, diode lasers and their controllers, and a LabView-based software
control system. The sensor head arrays are produced by anisotropic
etching of masked silicon wafers to produce multiple independent elements.
These arrays, having 10 and 32 individual, 0.81-mm2 elements
and 1.1-mm center-to-center spacing, are designed for flush mounting in
a hypersonic wind tunnel model. Laboratory calibration using dc and
low-frequency pressure ramps showed that the measurable displacement
resolution was approximately 0.01 µ, which corresponds in this
configuration to 0.1 psi. The frequency response is approximately 50 kHz
for 32 channels. The entire system is mounted on one laboratory rack for
installation near a wind tunnel facility.
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