Design and analysis of a swinging drag body flowmeter for irrigation pipe

A swinging drag body flowmeter was designed and tested under laboratory conditions. The meter was designed to measure flowrate in an irrigation water pipe. The meter consisted of a paddle, a rotating mechanism, and a potentiometer to measure paddle position. The rotating mechanism was mounted in a head unit that was strapped to a water pipe. The paddle extended from the rotating mechanism at the pipe wall, down through the center of the pipe. Drag and lift formulas were used to analyze flowmeter behavior and determine if these equations could be used to develop other flowmeters of this design. The lab data showed a strong correlation to the theoretical equations but there were significant errors between the two sets of data. The meter behaved in a repeatable and stable manner over two months of lab testing. It is believed that this design is particularly suited for irrigation pipe flow applications.