Cross-Wavelet Analysis on Radiation Emitted by the plume of a small-size Solid Rocket Motor

Abstract

This work follow a previous activity that developed a non-intrusive measurements technique for particles velocity ejected from a solid rocket motor based on wavelet analysis. The aim was to detect the particles passage and calculate the axial velocity through an auto-conditioned cross-correlation algorithm. In this study, a wavelet based processing techniques are applied and an innovative methodology based on the cross-wavelet analysis is presented. The objective is to detect the impulsive events associated to the particles crossing the field of view of the acquisition system. Starting from two synthetic signals characterized by a Gaussian peak, each one located at a different time instants, cross-wavelet analysis identify an increase of energy for all the correlation time producing a structure in the time scale comparable to the delay between the peaks. On the experimental database a continuous wavelet transform and a local intermittency measurement are performed to localize high energy events with randomic occurrence in the time series that are associated to the passage of allumina particles. Cross-wavelet analysis present several correlation structures localized in time between the events highlighted by the LIM maps. Results are very promising and could be a very interesting bases for deeper analysis based on wavelet, LIM and cross-wavelet.