ERSC 2P16 Lecture Notes - Lecture 17: Viscosity, Turbulence, Shear Velocity
6 Aug 2015
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Fluid gravity flows: viscous sublayer (vsl): the thickness of the vsl (d the lower case greek letter delta) is known from experiments to be related to the kinematic viscosity and the shear velocity of the flow by: It ranges from a fraction of a millimetre to several millimetres thick. The thickness of the vsl is particularly important in comparison to size of grains (d) on the bed (we"ll see later that the forces that act on the grains vary with this relationship). The boundary reynolds" number (r*) is used to determine the relationship between d and d: A key question is at what value of r* is the diameter of the grains on the bed equal to the thickness of the vsl? the condition exists when d. Turbulent boundaries are classified on the basis of the relationship between thickness of the vsl and the size of the bed material.
