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摘要
Particle image velocimetry (PIV) provides a field of discrete vectors to represent a continuum velocity field. Various methods have been adopted to evaluate the integrity of the discrete vectors. In contrast, the present communication provides a systematic technique whereby the integrity of the measured field can be assessed using basic topological principles. Starting with the recognition that PIV provides a vector field overlaid on a planar surface, the analyst can identify the holes (to be punched through the surface of a sphere) and the handles (to be added to the sphere's surface) that will represent the appropriate surface for the topological analysis. These operations define the a priori Euler characteristic (chi(A)) for the subject PIV image. The experimental Euler characteristic (chi(E)) will be known from the properties of the measured vector field: nodes, saddles, etc. A necessary condition for the integrity of the measured vector field is chi(E) = chi(A). The topological bases for the integrity evaluation, including the important constraint of ensuring a smooth collapsed sphere, are carefully explained and described with examples.
- 出版日期2016-9
- 单位中国人民解放军海军大连舰艇学院
