A SILICON TRANSDUCER FOR THE DETERMINATION OF WALL-PRESSURE FLUCTUATIONS IN TURBULENT BOUNDARY-LAYERS

Small and sensitive silicon sensors for turbulent wall-pressure fluctu ation measurements have been designed and fabricated using microelectr onic technology. For the detection of the pressure fluctuations piezor esistive gauges are placed on a diaphragm and the resistance of these gauges depends on the stresses in the diaphragm. For the determination of the performance of these pressure transducers comparisons with con ventional microphones were carried out in a well-defined two-dimension al boundary layer. Power spectra from the silicon pressure transducer revealed a slope in the inertial sublayer corresponding approximately to the 5/3-law of Kolmogorov, and the normalized wall pressure fluctua tions agreed well with other direct measurements.