BYPASS LAMINAR-TURBULENT TRANSITION
IN A THERMAL BOUNDARY LAYER
E. Ya. Epik

UDC 536.24:532.526

We present results of four series of experimental 
investigations of the bypass laminar-turbulent transition (BLTT) initiated 
by actions of different nature (higher than usual degree of turbulence 
of the external flow, closed laminar separation at the leading edge, 
and their combination) on a flat surface in gradient-free flow. Our 
findings have supported the idea that strongly disturbed flows have 
a tendency toward the formation of an upper thermal bypass laminar-turbulent 
transition whose heat-transfer coefficient changes monotonically because 
of the formation of a pseudolaminar boundary layer before it. The 
influence of the scale of turbulence on the position of a bypass laminar-turbulent 
transition and the intensification of the transfer processes in the 
boundary layers formed before and after the bypass laminar-turbulent 
transition has been evaluated. We have developed a complex method 
for diagnostics of a bypass laminar-turbulent transition, which allows 
one to establish the fact of formation of the bypass laminar-turbulent 
transition and determine its starting and end points.

Institute of Technical Thermal Physics, National Academy 
of Sciences of Ukraine, Kiev, Ukraine; email: epik@epik.kiev.ua. Translated 
from Inzhenerno-Fizicheskii Zhurnal, Vol. 74, No. 4, pp. 105-110, 
July-August, 2001. Original article submitted November 29, 2000.

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