Study of the effect of beam spreading on systematic Doppler flow measurement errors

Doppler ultrasonic flowmeters are based on a single ray approximation. We have studied the effect of beam spreading on the systematic Doppler flow measurement by developing a theoretical ray tracing model and validating the same with experiments. This paper will discuss experimental work and the use of ray tracing and finite element models to investigate this effect. This paper indicates some early trends which we have identified, but should be treated as "work in progress".