Simultaneous reconstruction of flow and temperature cross-sections in gas jets using air-coupled tomography

This paper describes a technique whereby air-coupled ultrasonic techniques can be used to collect through-transmission data from gas jets. A transducer pair was scanned in two-dimensional section at an angle to the jet, and travel time and amplitude data recorded along various paths in counter-propagating directions. Suitable processing of the data, followed by tomographic reconstruction techniques, then allowed images to be formed of variations in either temperature or flow velocity. Results have been obtained using heated jets, where it has been shown that it is possible to separate the two variables successfully.