軸流ファンの動翼後縁近傍のカルマン渦の挙動に関する研究

抄録

In the present paper the attention is focused on the characteristics of Karman vortex shedding from the trailing edge of the rotor blade at the design operating attack angle for different Reynolds number. We measured the local relative velocity, velocity fluctuation, and spectrum in the near wake of rotor blade. The periodic velocity fluctuation in the near wake of the blade was observed at Reynolds number, based on the tip chord length, of 5.1×10⁴. This was caused by Karman vortex shedding from the trailing edge of the blade at constant frequency along spanwise direction. However, as Reynolds number increased, the spectrum of velocity fluctuation became broad band gradually. At the design operating point, the velocity fluctuation at predicted vortex shedding frequency was also observed in the near wake of the rotor blade momentarily although the intensity and the periodicity of velocity fluctuations became weak.