ギャップをもつ粗さ要素を通過する乱流境界層における二次流れの挙動

概要

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In a turbulent boundary layer through gaps between roughness elements, behavior of secondary flow and streamwise vortices generated due to the three-dimensional roughness has been studied experimentally. Measurement was made on four different gap sizes, G=δ_0/8,δ_0/4,δ_0/2 and δ_0. Qualitative feature of secondary flow is similar in the four gap sizes. Positive and negative streamwise vortices exist behind the roughness and decay in a spanwise divergent flow field. In the decay process, strength of these vortices keeps the largest value at the smallest gap size, G=δ_0/8. Streamwise vorticity has influence on magnitude of main rate of strain ∂U/∂y associated with the gap size and suppresses the mixing length scale. A ratio of the transverse and spanwise mixing length scales qualitatively depends on a corresponding deformation rate ratio.
一般社団法人日本機械学会の論文
1998-02-25