1992 年 12 巻 1Supplement 号 p. 51-54
An image processing technique based on particle-tracking has been developed to obtain instantaneously two components of velocity on many of the sections in three-dimensional space. The tracer particles in a semicylinder tank were visualized on several horizontal sections by means of parallel laser-light sheets generated from a scanning laser beam. The movements of the particles were recorded by a high-speed video system synchronized with the scanning. Since the obtained vectors were interpolated at the grid points on boundary-fitted coordinates (BFC), the derivation of vorticities were conveniently carried out in the transformed field of the BFC. As a result, the two-dimensional aspects of the complicated flow were captured over three-dimensional space.