Measurement of convective heat-transfer coefficients on a wind tunnel model by passive and stimulated infrared thermograpy

Research conducted at ONERA to make quantitative infrared thermography operational and applicable to any 3D model is discussed. The problems of precise thermometry using this technique are considered, and the methodological and hardware choices made to obtain quantitative thermograms are described. The problem of determining the convective flows once the unsteady temperatures are known is addressed for two kinds of methods: classical passive thermography, in which only the heating due to convection is used, and active, or stimulated, thermography, in which the heat-transfer coefficients are calculated directly from the additional heating of the model by a radiation source, applied for short periods during the test.