抄録
The two dimensional turbulent jet impinging to a circular cylinder has been investigated. The distinct decrease of the stagnation pressure against the total pressure in free jet was observed with generation of tone between the exit of jet and the cylinder in range of 3≦x_c/h≦10 where x_c is the streamwise position of the cylinder and h is height of the jet exit. To reveal the mechanism of this self-excited oscillation, the velocity profiles and the spectrum of the velocity fluctuation upstream the circular cylinder has been measured using hotwire anemometry. The velocity spectrum shows that the flow has the periodical flow structures whose frequency coincides with that of the tone, and that the flow structures impinging to the cylinder might makes pressure fluctuation at the cylinder surface.
