Abstract
Laser interferometry can be used to measure the average temperature field in a fluid, integrated over the length of an experimental model. However, such measurements are inherently approximate when there is a temperature variation in the direction of the test/object beam. The present study examines the accuracy of beam-averaged interferometric measurements made in ideal gases. An analysis is performed to determine the accuracy of both beam-averaged temperature and heat transfer rate measurements. The heat transfer results are obtained for simulated measurements of forced convection from a plate with a power function temperature variation in the beam direction. The results show that the error in the beam-averaged temperature field is less small, even for the most adverse temperature distribution in the light beam direction. However, it was found that the error in the beam-averaged heat transfer rate can be greater than ten percent for some conditions.
