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A description of infrared thermography, as tbis Is eJq)loyed In a hypersonic blowdown wind tunnel for the acquIsition of high quality "two-dimensional" heat transfer data over aerodynamic surfaces, Is given. It Is shown that the availabillty of an Infrared scanning radiometer and a standard dlgital lmage processing (DIP) system In the laboratory may provide the means for the performance of highly effident (In terms of time and cost) heat transfer measurements, which exhibit accuracy levels comparable to those achieved by classical discrete point gauges, such as thin film surface resistance thermometers and thermocouples. The advantuges of infrared thermal mapping over the classical techniq�s, not ooly In measuring heat transfer distributions over cOJq)lex three-dimensional configurations andIn locating and quantifying bigbiy localized hot spots, but also In interpreting puzzling results observed on simple configurations are illustrated by means of a series of eX8Jq)les. A discussion of the limitations of the technique Is also offered to Indicate that most of such limitations are common to class ical "zero-dlmenslonal" Instrumentation as well Manuscript

This paper presents a method to calibrate the frequency response characteristics of fast response pressure transducers. The method is shown to give good results up to frequencies of at least 50 kHz. Then the frequency response of a pressure measurement system, consisting of a short tube followed by one of these transducers, is calibrated. A theoretical model describing the frequency response of the same pressure measurement system is translated into a computer program and shown to provide excellent agreement with the measurements. This model is then also used to compute response times of measurement systems. Using the computer model, a test setup is designed to measure high frequency components at low pressures with a microphone, which is shown in situ to give good results.

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