Abstract: A method of determining flow speed in a low pressure environment. The method includes obtaining bi-directional acoustic data from a plurality of transducer pairs as a fluid moves relative to the plurality of transducer pairs. The method further includes measuring phase lags corresponding to the bi-directional acoustic data, and determining bi-directional flight times using the phase lags. Additionally, the method includes calculating a flow speed of the fluid corresponding to each transducer pair from the bi-directional flight times. The method includes correcting for at least one of temperature effects, pressure effects, and wake effects, using a system model. The method further includes generating a report including the flow speed of the fluid.

Abstract: Ultrasonic transducers which include at least one internally directed generally concavely configured sonic energy radiating element which directs sonic energy toward at least one arcuate energy reflecting surface which redirects and focuses the energy through an opening in a housing defining the transducer. The configuration of the at least one radiating element and the at least one energy reflecting surface are such that sound waves from substantially any point along the radiating element to the reflecting surface and to a focus exteriorly of the opening are substantially equal. The transducers function to focus energy either as transmitters or receivers.

Abstract: An ultrasonic testing method and apparatus which includes synthesizing impulse response images using specially constructed waveforms. The apparatus includes a waveform generator, transducers for transmitting and receiving the ultrasonic signals and a digital signal processor or computer for efficiently processing the captured signal data to form the desired impulse response signals.