| Popis: |
The results of experimental study of boundary layer laminar-turbulent transition on a blunted plate with leading edges of various shapes and thicknesses at free-stream Mach number M=5 and unit Reynolds numbers Re1 from 1.5x107 to 9x107 m-1 are presented. The Reynolds number Reb, calculated by leading edge thickness b, was varied from 0 to 2x106. The following leading edge shapes were studied: cylinder, flat face, ellipse, and \"smoothed cylinder\". They were chosen by the results of numerical study of a non-viscous gas flow around a blunted plate. It was shown that at Reb0.5x105, the shape of the leading edge practically does not affect the transition position. At the same time, the laminar flow segment is monotonously extended as b increases. For large Reb values the variation of leading edge shape significantly changes the transition position. A laminar - turbulent transition reversal was observed for all investigated shapes of leading edge. However, the Reynolds number Reb, at which the reversal occurs, depends significantly on the edge shape. The possibility of laminar flow segment extension by reasonable selection of blunting shape and thickness is shown. |
