Application of multiresolution analysis for simultaneous measurement of gas and liquid velocities and fractional gas hold-up in bubble column using LDA

A new strategy using wavelet transforms for multiresolution analysis of bub ble column hydrodynamics from laser Doppler anemometer measurements of the axial velocity has been formulated. The advantage of the methodology is tha t we may infer intrinsic features of the bubble column hydrodynamics by acc urately detecting the passage of bubbles at local positions in the column. The detection of bubbles was possible by denoising local time series data a nd analyzing for its intermittent behavior. The methodology allows for calc ulating the changes in the local average liquid velocities and local gas ho ld-up and was related to the intermittent nature Of turbulence in the syste m. The variation in these properties and flow behavior as a function of rad ial distance have been studied. (C) 2001 Elsevier Science Ltd. All rights r eserved.