乱流境界層における等速度点集合のフラクタル性 : 第2報, レイノルズ応力との関連

In this report, the relationship between iso-velocity sets of a turbulent boundary layer and instantaneous Reynolds stress is investigated by means of quadrant analysis. The fractal feature of iso-velocity sets belongs to the positive instantaneous Reynolds stress region, that is, the second or the fourth quadrant. Moreover, when this instantaneous Reynolds stress is two times larger than its time averaged value, iso-velocity sets show the faractal aspect. We use the method of the probability distribution function for fractal analysis. Scale similarity extends from the Kolmogorov scale to the large eddy scale. This is the first attempt to clarify the relationship between the fractal feature and the most important physical quantity in the turbulent boundary layer.