渦誘起ジェットによる円すいディフューザ内はく離流の制御(<小特集>乱流せん断流の制御)

概要

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The aim of the present study is to clarify the applicability of vortex generator jets (VGJs) in the control of flow separating in a conical diffuser. Systematic experiments were made to investigate longitudinal streamwise vortices induced by eight jets issued from the wall of a circular pipe having 125mm dia., where VGJs of 6 mm dia. pitched at 30deg and skewed at 90deg. The distributions of wall friction show that turbulent mixing in the boundary layer is enhanced by corotating type VGJs. By using a typical VGJ which was installed at the inlet of a 14 deg conical diffuser with an area ratio of 2.56, the separation in the diffuser was almost suppressed, and the pressure recovery coefficient increased from 0.63 to 0.68 at a velocity ratio Vj/U of 1.9. To quantify the structure of flow separating in a diffuser, attempts were made to measure the fraction of backflow with an X-type hot-wire velocimeter.
社団法人日本機械学会の論文
1997-01-25