Development of high accurate environmental flow measurement system using ultrasound

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Drinking and agricultural water is supplied from rivers, lakes, and reservoirs. And recently, water pollution with domestic wastewater, from factories, and slack and the propagation of microbes is worsening especially in Asia. For this environmental problem, international study cooperation and the development of comprehensive technologies for water pollution control are demanded.In the present study, the investigation on the application of ultrasonic Doppler method with high accuracy measurement to the environmental flow is reported. This method uses a pulsed ultrasonic echography together with detected instantaneous Doppler shift frequency to form a velocity profile. Velocity profiles measured by this method and the Electromagnetic Current Meter were compared, and similar profiles were obtained. Since Ultrasonic Doppler Method is a line measurement, a two-dimensional velocity vector can be obtained on the crossing point of two measuring lines. And by setting up the transducer accurately using RTK-GPS, a two-dimensional flow mapping can be formed.Ultrasonic Doppler method was applied to a river flow in order to apply to Environmental flow mapping. The measured velocity profiles show that microparticles in the river are enough to reflect the ultrasonic echo, and mean velocity profiles from Ultrasonic Doppler method and Electromagnetic Current Meter agree well. By applying RTK-GPS to obtain the information of the transducer position, the vector field by two-dimensional flow mapping using Ultrasonic Doppler method and RTK-GPS shows clearly the river flow.