| 摘要 |
PURPOSE:To increase the thickness of a turbulent boundary layer by arranging articles on the lower surface wall of a wind tunnel at constant spacings over the whole width of the wind tunnel. CONSTITUTION:Articles 12 are arranged in a line at spacings each equal to a center to center distance S in the direction of a width D over the whole width D on the lower wall surface 11 of a wind tunnel 10. Figs. A-K are the side views of the articles 12 used and, for example, the widths D take values (cm) as shown and heights are unified to 10mm. Figs. C-E show triangular flat plates with apex angles 53, 40 and 30 deg. and Figs. H and I illustrate cones with apex angles 53 and 30 deg. respectively. To increase the thickness of a turbulent shear layer and make the layer have the same characteristics as naturally transitional flow characteristics, it is effective to make the configuration of the article 12 the triangular flat plate (Fig. E) or the cone (Fig. I) with a 30 deg. apex angle and a height as large as possible. Thus, the thickness of the turbulent shear layer is increased and the flow characteristics and the same as those of naturally transitional flow whereby an accurate experiment can be executed and the making and setting of an apparatus are facilitated.
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