Abstract
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.
