後向きステップ底面の再付着域の伝熱特性に対する主流乱れの影響 : はく離角度の変化する場合

概要

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The effect both of free-stream turbulence and of separated angles on heat transfer characteristics in the reattachment region under the condition of a two-dimensional backward-facing step have been experimentally investigated. The turbulence intensity T_u and the separated angle 2θ were controlled by varying the vertical angle of the triangular cylinder with a tail plate, and the mesh of turbulent screen, respectively. The effect of T_u on the reattachment length X_r was found to be not uniform with respect to 2θ. The maximum heat transfer coefficient h_<max> was obtained at point that appears in the upstream side of the reattachment point by about one step hight, for all combinations of 2θ and T_u employed in this study. The value of h_<max> increases with a decrease in X_r. The decrease results from an increase in T_u or a decrease in 2θ. It was fount to be inappropriate, however, to relate both h_<max> and X_r either directly or quantitatively. The change in h_<max> with 2θ and T_u may rather depend upon both changes in the following properties (1) the maximum gradient of wall static pressure in the recirculation region ; and (2) the maximum intensity of pressure fluctuation.
一般社団法人日本機械学会の論文
1986-07-25