後流の周期変動現象と後流特性量との関係について

概要

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We made an experiment on periodic fluctuation phenomenon in the wake vortex and the characteristic with bluff body. We adopted shape of the bluff body , such as flat type wing and wage type wing to fix the trading edge separation point, and researched that the scale of vortex changed in shape of the bluff body, even if the thickness and chord length of the body are same. These experiments were practiced using wind tunnel and the Reynolds number was Re =7.6×10^4, 1.1×10^5 which was transition zone, such as middle flow between laminar flow and turbulent flow. In this paper, we find relationship between Strouhal number for equation of noise predict and vortex shedding frequency at trading edge, and appropriate the representative length. The experimental results show that in such a bluff body, the representative length in the Strouhal number is twice as large as displacement thickness of the wake and the vortex shedding frequency are correlated this Strouhal number.