Ultrasonic metering of flow velocity based on transit time differentials

Abstract

The technique of ultrasonic metering of flow velocity is rapidly progressing in various aspects of its scientific and technical applications. The accuracy of these measurements is very high, but not as high as could be desired. The author presents some results of a search for sources of error. The simplest case is analysed; uniform flow of a homogeneous fluid measured with small ultrasonic probes. The analysis proceeds with a decomposition of the sound path into two components, which are named 'carry-off' and 'vibrational'. An exact formula is derived, which resembles the well known Lorentz transformation formula.