Development of ultrasound Doppler velocimetry technique applying cross-correlation processing

Ultrasound Doppler Velocimetry technique (UDV) applying Doppler effect has been developed for measuring velocity distributions of sodium flow. As Doppler shift frequency is proportional to velocity of microparticles carried by flowing liquid, it is possible to evaluate velocity distributions of flowing liquid from Doppler shift frequency. In this report, a technique applying cross-correlation processing is proposed to derive Doppler shift frequency from the echoes of ultrasonic pulses. Verification studies of the proposed technique are conducted based on simulated echoes and actual echoes in water tests. Main results are as follows: (1) As the result of verification studies conducted based on the simulated echoes, relative error estimated by the proposed technique is about 1 percent. (2) The proposed technique is an effective measures for the reduction of noise signals. (3) The velocity distributions of water flowing in a pipe are evaluated in the experiments. The velocity distributions evaluated by the proposed technique is almost equivalent to that of turbulent flow evaluated by 1/7th power law. (author)