Air sparging has shown to enhance the flux during the nanofiltration of liquid/liquid suspensions in a flat sheet module. So this study focuses on the characterisation of an intermittent gas-liquid two-phase flow in a flat-sheet geometry, in order to understand how air sparging can enhance the flux. The gas-liquid two-phase flow was characterised experimentally by ima ge analyses and numerical simulation using the Fluent code. Experimental and computed values of the shape of the bubbles and of their upward velocity were compared. The characterisation was made without superficial liquid velocity and at a very low superficial gas velocity. In these conditions, an isolated spherical cap bubble could be observed.