Journal of Fluid Mechanics



On the criteria for reverse transition in a two-dimensional boundary layer flow


M. A. Badri  Narayanan a1 and V.  Ramjee a1
a1 Department of Aeronautical Engineering, Indian Institute of Science, Bangalore, India

Article author query
narayanan ma   [Google Scholar] 
ramjee v   [Google Scholar] 
 

Abstract

Experiments on reverse transition were conducted in two-dimensional accelerated incompressible turbulent boundary layers. Mean velocity profiles, longitudinal velocity fluctuations $\tilde{u}^{\prime}(=(\overline{u^{\prime 2}})^{\frac{1}{2}})$ and the wall-shearing stress (TW) were measured. The mean velocity profiles show that the wall region adjusts itself to laminar conditions earlier than the outer region. During the reverse transition process, increases in the shape parameter (H) are accompanied by a decrease in the skin friction coefficient (Cf). Profiles of turbulent intensity (u2) exhibit near similarity in the turbulence decay region. The breakdown of the law of the wall is characterized by the parameter \[ \Delta_p (=\nu[dP/dx]/\rho U^{*3}) = - 0.02, \] where U* is the friction velocity. Downstream of this region the decay of $\tilde{u}^{\prime}$ fluctuations occurred when the momentum thickness Reynolds number (R) decreased roughly below 400.

(Published Online March 28 2006)
(Received March 13 1967)
(Revised March 28 1968)



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