Abstract
Development of a simple three-dimensional velocity vector measurement system is expected in order to analyze a highly complex flow field.
This paper presents a new measurement system of three-dimensional velocity vectors in a flow field based on color information. In this system, tracer particles are visualized by a color spectrum slit method which uses a prism spectrum. The color of a tracer particle can determine its position in one direction. In the other two directions, the tracer particle can be tracked on the two-dimensional tracer images by using both a correlation and a particle tracking methods. Consequently, a three-dimensional velocity vector is obtained. The system has been developed and actually applied to a uniform flow and a flow around a sphere in a water channel and the measurement uncertainties were evaluated. The results agree well with a typical pattern of the flows.
In comparison with a conventional stereoscopic measurement method, in which each tracer is tracked in a three-dimensional space, the largest advantage of this method is that a three-dimensional velocity vector distribution in a flow field is easily obtained by adding a color image processing to a simple technique of two-dimensional velocity vector measurement.
