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 Behavior of Vortex Shedding from Trailing Edge of Rotor Blade of Axial Flow Fans
In the present paper the attention is focused on the characteristics of Karman vortex shedding from the trailing edge ofthe 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 theblade was observed at Reynolds number, based on the tip chord length, of 5.1×10<SUP>4</SUP>. This was caused by Karman vortexshedding from the trailing edge of the blade at constant frequency along spanwise direction. However, as Reynolds numberincreased, the spectrum of velocity fluctuation became broad band gradually. At the design operating point, the velocityfluctuation at predicted vortex shedding frequency was also observed in the near wake of the rotor blade momentarilyalthough the intensity and the periodicity of velocity fluctuations became weak.
ターボ機械 40(7), 441-447, 2012-07-10
Turbomachinery Society of Japan