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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

A VISUAL STUDY OF EFFECT OF HEATING ON BURST OF TURBULENT SPOTS

Get access (open in a dialog) DOI: 10.1615/IHTC11.2450
pages 75-80

Аннотация

The effect of heating on the transitional processes, especially on the burst of turbulent spots on the surface of streamlined body of revolution are studied experimentally in water tunnel. The burst of turbulent spots and effect of heating on it are visualized with method of direct injecting color liquid into the sublayer of laminar boundary layer. The transition processes of boundary layer were viewed and recorded with IKegami HC— 340 high—speed video system which can provide 25 frames picture per second with an effective shutter speed of 250us. The burst frequency of turbulent spots evidently decrease and the average distance between two spots in transerve increase with the increase of surface temperature difference to free stream flow. The burst frequency of turbulent spots decrease and finally reach to an unchanged value with the surface temperature difference of about 20C. The average location of burst of turbulent spots in streamwise extent change a little in heated surface with high turbulence level of about 1%in free stream flow. This has the obvious difference to that in low turbulence intensity (< 0. 2%)flow.