Can the transport of intensity equation be used to perform non-intrusive temperature measurements in liquids?

This study attempts to take advantage of the optical features of fluids to perform non-intrusive measurements of two-dimensional temperature fields. To this aim, we test the capability of the so-called ‘transport of intensity equation’ to evaluate the phase shift and the corresponding temperature field in liquid media. In this short paper, we provide a brief description of this methodology, and we show an example of our preliminary results obtained by investigating the thermal boundary layer, which develops around a hot, thin, horizontal wire immersed in a pool of subcooled deionized water.