Preventing transition to turbulence: a viscosity stratification does not always help.
In channel flows a step on the route to turbulence is the formation of streaks, often due to algebraic growth of disturbances. While a variation of viscosity in the gradient direction often plays a large role in laminar-turbulent transition in shear flows, we show that it has, surprisingly, little effect on the algebraic growth. Nonuniform viscosity therefore may not always work as a flow-control strategy for maintaining the flow as laminar.
Engineering Mechanics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India.
Vijayakumar
V
Chikkadi
A
A
Sameen
Rama
R
Govindarajan