乱流温度変動計測における細線温度センサの空間分解能と応答補償

抄録

For accurate measurement of fluid temperature fluctuations by a fine-wire temperature sensor (coldwire), it is necessary to keep the sensor length about 1000 times larger than its diameter to avoid the deterioration in temporal response. However, a longer sensor unfortunately reduces its spatial resolution. In the present study, we have tested the performance of fine cold-wires of several different sensor lengths, and examined the effects of the temporal and spatial resolutions on the rms values, power spectra and instantaneous signal traces of temperature fluctuations in a canonical turbulent thermal boundary layer. It is found that applying the response compensation to the outputs of cold-wires with a relatively small length-to-diameter ratio enables us to avoid the deterioration in spatial resolution and to obtain sufficiently accurate measurement results.