Title :
Statistical Analysis of High-Speed Schlieren Imaging in PAC
Author :
Cantoro, Gianmatteo ; Colombo, Vittorio ; Concetti, Alessia ; Ghedini, Emanuele ; Sanibondi, Paolo ; Zinzani, Filippo
Author_Institution :
Dept. of Mech. Eng. (D.I.E.M.), Univ. di Bologna, Bologna, Italy
Abstract :
The interaction of plasma gas with the surrounding atmosphere in plasma arc cutting (PAC) has been investigated using high-speed Schlieren imaging. The time series corresponding to the recorded intensity of each pixel have been postprocessed using statistical analysis. Two different methods that highlight the time variation of the amplitude of the fluctuations in the density field have been compared: the windowed standard deviation and the Generalized Autoregressive Conditional Heteroskedasticity (GARCH) approach. Whereas a mean-variance analysis can provide at most time-averaged results, GARCH can model the instantaneous variation of the luminous signal, thus providing new insights on the time evolution of the turbulence around the arc.
Keywords :
arc cutting; arcs (electric); high-speed optical techniques; plasma diagnostics; plasma fluctuations; plasma interactions; plasma materials processing; plasma turbulence; schlieren systems; statistical analysis; time series; GARCH model; PAC; amplitude fluctuation time variation; density field fluctuation; generalized autoregressive conditional heteroskedasticity method; high-speed Schlieren Imaging; instantaneous luminous signal variation; mean-variance analysis; pixel intensity; plasma arc cutting; plasma gas-atmosphere interaction; statistical analysis; time series; turbulence time evolution; windowed standard deviation; Gaussian noise; Imaging; Pixel; Plasmas; Statistical analysis; Time series analysis; Visualization; Plasma diagnostics; plasma materials processing; plasma sources;
Journal_Title :
Plasma Science, IEEE Transactions on
DOI :
10.1109/TPS.2011.2148128
