翼の遠方後流の特性と渦スケールの算出

抄録

Eddy scale what is one of indices for evaluating the turbulent flow field is calculated from cross-correlation, auto-correlation, energy spectrum, half width etc...The difference in practicality due to these calculation methods was verified by comparing them quantitatively using experiments data which measured by wind tunnel experiments. In the experiment, the NACA0012 airfoil with a chord length 150mm, an aspect ratio of 4.27, and a span length of 870mm was used, and the average flow velocity, velocity fluctuation, energy spectrum, auto-correlation and cross-correlation of the far wake of the blade were measured using a hot wire anemometer. The measurement was performed two-dimensionally. From the experimental results, it is considered that the wake of the blade flows while maintaining the structure even at a distance of 13 times the chord length (X/C=13). From the correlation coefficient distribution chart, the eddy structure at the position of X/C=10 was identified no uniform isotropic. The eddy scale calculated from auto-correlation has a certain level accuracy, but cannot be said to be practical. The eddy scale accuracy what calculated from the half-width and power spectrum length were proven exceedingly bad, and practicality is poor.