Co-circulation of gas and liquid in a pipe can generate,depending on inlet conditions,various kinds of flow patterns.Few investigations have been performed on intermittent two-phase flows (slug flows) using classical techniques show that nuclear magnetic resonance is a powerful technique to study such flows.The presented results dealwith controlled isolated Taylor bubbles.In addition to a classical Pulsed Field Gradient Spin Echo (PFGSE),a magnetic field gradient was applied during the #pi#/2)_x radio requency pulse,which produces a selective irradition.Thus,cutting up of the flow into slices provides the ongitudinal evolution of the liquid fraction and of the velocity probability distribution in the entire region perturbed by the Taylor bubble.The existence of a recirculatory flow under the Taylor bubble is clearly demonstrated.
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