ISSN 1002-1027  CN 11-2952/G2

Acta scientiarum naturalium Universitatis Pekinensis

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Experimental Research on the Mechanism of Reverse Transition in Turbulent Boundary Layer

ZHANG Zhen1, SUN Zhili2, YAN Dachun2   

  • Received:2005-03-16 Online:2006-05-20 Published:2006-05-20

Abstract: Experimental research on the phenomenon of reverse transition in the boundary layer under a heated plate is presented, and the mechanism of reverse transition is also explained. During the experiment, the production term, dissipation term as well as absorption term of turbulent energy is measured. Experimental results show that, through the formation of stably stratified structure, the production term of turbulent energy in the range between 400 - 1000 mm away from the leading edge of the plate has become negative, so the region is actually an absorption region of turbulent energy. In the same time, the dissipation term near the wall region is strengthened by smallscale eddy. Under the conjunct effect of the negative production term, the absorption term, as well as the absorption term caused by buoyancy, the turbulent energy in the inner layer of turbulent boundary layer is depleted rapidly, and the turbulent flow in the outer layer changes into passive flow because of the lack of energy source. Finally, the turbulence turns into laminar flow.