Measuring water flow velocity and discharge with acoustic doppler velocimeter (adv)

The discharge measurement in river is the basis for using of water, planning, designing and operating water management and development projects. The traditional method of measuring the discharge is based on measurement of the water velocity and cross section area. Current meters are commonly used to determine of water velocity but they require calibration at frequent intervals in laboratory flumes to get accurate results. Because cup and propeller equipments of current meters may be physically damaged, especially river conditions. Recently, acoustics velocimeters are increasingly used with the advances in remote sensing and data processing techniques. There are currently several manufacturers of commercial acoustic devices but the general principles of operation are based on the Doppler shift effect which is the difference in frequency (shift) between transmitted pulses and received echoes in water. Acoustics velocimeters provide accurate and economical discharge measurements with simple and fast operation under different flow conditions. The purpose of this paper is to present principles of operation of acoustic Doppler velocimeters with results of field and open channel discharge measurements