Influence on the accuracy of Clamp-on ultrasonic flowmeters due to the recombination of multiple propagation paths

Clamp-on ultrasonic flowmeters geometry includes four different materials in the ultrasound propagation path: wedge, coupling material, pipe and liquid. In this case, oblique incidence ray generated by the emitter transducer is splitted into several rays caused by multiple reflections in pipe wall or because of propagation mode conversion at interfaces. These multiple paths are recombined at the reception transducer aperture, producing a single signal whose amplitude and phase depend on which proportion each paths contributes. The objective of this work is to quantify this phenomenon and analyses the implications it has on the accuracy of Clamp-on ultrasonic flowmeters.