Abstract: A method for determining constituent fluids for a multiphase flow in a pipe is provided by mounting two transducers on a pipewall. The first and second transducers are longitudinally offset in a longitudinal direction parallel to the flow. A first sonic wave is generated through the pipewall and is split into a pipewall wave and a transverse wave. The pipewall wave travels in the pipewall directly between the transducers, and the transverse wave is reflected through the flow between the transducers. With knowledge of one of the fluids in the flow, attenuation is measured of the transverse wave relative to the pipewall wave to determine proportions of constituent liquids in the flow. Amplitude fluctuations are determined in the transverse wave relative to the pipewall wave, and based on the amplitude fluctuations, proportions of gas bubbles in the flow are determined.