Abstract
Model turbulent kinetic energy profiles expected during drag reduction are synthesized from similarity arguments. At low drag reduction, it is postulated that the radial transport of turbulent kinetic energy and of axial momentum are analogous. Thus, in nondimensional terms, the maximum kinetic energy during drag reduction must exceed the Newtonian maximum kinetic energy by an amount proportional to the ’’effective slip,’’ which latter is the amount whereby the mean velocity during drag reduction exceeds that during Newtonian turbulent flow. At maximum drag reduction, the turbulent kinetic energy profile is related to the Newtonian profile by means of the respective mixing length constants, Xm and Xn; in the former case, the maximum turbulent kinetic energy is predicted to be Xn/Xm = 4.7 times the Newtonian. The model profiles are in accord with the (few) available experimental measurements of turbulence during drag reduction.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
