A new correlation method for transit-time estimation

Abstract A new correlation method for transit-time estimation is proposed. The transit-time of a propagating quantity between two points along the propagation path could be measured by noise analysis technique when this quantity conveys some measurable stochastic signal with it. This is usually performed by observing directly the peak in the cross-correlation function of the stochastic signal measured at two points in the propagation path, or indirectly by reading the slope of the phase-angular frequency curve. The proposed method presents the transit-time information directly in the same way as in the ordinary cross-correlation technique, but with a better resolution when the conveyed noise signal is band-limited. It also rejects extraneous noise contamination when such noise appears in a narrow frequency band. The usefulness of this method was tested in an air-water two-phase flow channel to estimate the transit-time of the bubbles.