ENGINEERING LASER-BASED DIAGNOSTIC IN A HOT WIND TUNNEL JET: MEASUREMENT OF THE TEMPERATURE STRUCTURE COEFFICIENT BY USING AN OPTIMIZATION TECHNIQUE

This paper is devoted to an engineering laser-based diagnostic technique which is able to extract the value of the temperature structure coefficient in a hot turbulent wind tunnel jet, by using a thin laser beam which is sent into the jet. Some experimental investigations are carried out to characterize the jet under study and the probabilities of the positions of the laser beam impact on a photocell are measured. The theoretical values of the same probabilities are computed by assuming that the laser beam direction is a Markov random process. By means of an optimization technique with constraints, based on the Golden Section algorithm, the temperature structure coefficient of the jet is determined. The validity of the result obtained is proved by a good agreement which is observed in the comparison between another parameter computed from that result and the previously published data.