Measurement of Three Dimensional Velocity Vectors in a Flow Field Based on a Spatio-Temporal Correlation Method
Ichirô KIMURA, Yoshiharu Kohno, Toshi TAKAMORI · Transactions of the Society of Instrument and Control Engineers · 1991
A measurement system of three-dimensional velocity vectors is essential in analyzing a highly complex flow field.This paper presents a new measurement method of three-dimensional velocity vectors in a flow field using a spatio-temporal correlation method.It is an advanced method for two-dimensional velocity vector measurement using correlation.The method needs two tracer particle images observed at a short distance in the flow direction.Each of the two images consists of frame time series.The two-dimensional information on velocity can be obtained using spatial correlation.In addition, the other one-dimensional information on velocity can be obtained using temporal correlation.Consequently, a three-dimensional velocity vector distribution is obtained by calculating spatio-temporal correlation between the two images.This system is actually applied to a steady flow field and the measurement uncertainty is evaluated.In comparison with a conventional stereoscopic measurement method, in which each tracer is tracked in a three-dimensional space, there are the following advantages in this method.1) The method has wide applications to flow visualization techniques because each tracer particle is not tracked but an image of tracer particles is observed as a spatial pattern.2) A spatially high density vector distribu-tion is obtained on a flow section.3) The method fundamentally needs not any known information on the flow characteristics.