Real time gas flow distribution measuring system using nonlinear acoustical sounding

Flow measurement by using ultrasonic waves has been used widely, because it does not disturb the flow field. But the conventional methods give only the average flow velocity between the ultrasonic transmitter and receiver. If we want to know the distribution many stations must be arranged surrounding the observation area and tomographic image reconstruction algorithm is required. In this paper a completely new method which can get the distribution of flow velocity along a desired line from only the ultrasonic data obtained by two stations located at both ends of this line. For this purpose the nonlinear interaction between an impulsive pumping wave and the medium is used with another probing ultrasonic wave to detect it. The principle and some experimental results are given