7. TURBULENCE 7.1 What is turbulence? 7.2 Momentum transfer in laminar and turbulent flow 7.3 Turbulence notation 7.4 Effect of turbulence on the mean flow 7.5 Turbulence generation and transport 7.6 Important shear flows Summary Examples
PART (a) – THE NATURE OF TURBULENCE 7.1 What is Turbulence? Instantaneous Mean
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A “random”, 3-d, time-dependent eddying motion with many scales, superposed on an often drastically simpler mean flow. A solution of the Navier-Stokes equations. The natural state at high Reynolds numbers. An efficient transporter and mixer ... of momentum, energy, constituents. A major source of energy loss. A significant influence on drag and boundary-layer separation. “The last great unsolved problem of classical physics.” (variously attributed to Sommerfeld, Einstein and Feynman)
7.2 Momentum Transfer in Laminar and Turbulent Flow
In laminar flow adjacent layers of fluid slide pas..