乱流境界層における等速度点集合のフラクタル性 : 第3報, バーストとの関連

The purpose of this paper is to consider the relationship between the fractal aspect of iso-velocity sets and bursting phenomena in the wall region of a turbulent boundary layer. Burstings are detected by means of the VITA technique and quadrant analysis. With conditional averaging methods, we make it clear that the fractal features of iso-velocity sets depend only on the burstings that are detected by quadrant analysis but are independent of ones detected by the VITA technique. We also investigate the detective functions of bursting defined by each method. They have quite different statistical properties, and that of the quadrant technique has fractal structure. If detective function expressed the distribution of burstings, self similarity would remain in that distribution. This result suggests that burstings should be studied from the dynamical point of view.