LIST OF SYMBOLS (cont.) 



L lift force due to unsteady mean flow 



L' lift force due to turbulence 



m, n subscripts 



N 1 number of particles of size D per unit area 



of bed surface 



p probability of the lift force exceeding sub- 



merged weight 



P pressure 



q oscillatory bed-load rate 



B 



Q steady mean bed-load rate 



r cylinder radius (Jeffreys model) 



R resultant of all hydrodynamic forces exerted 



on a solid particle 



t =i- 

 1 V 1 exchange time 



2TT 



T = — period of oscillation 



U) 



T temperature degrees Fahrenheit 



u, v instantaneous boundary layer velocity 



components 



u, v unsteady mean velocity components in the 



boundary layer 



u* , v* turbulent velocity components in the 



boundary layer 



u , v unsteady mean velocity components at the 



boundary from irrotational theory 



v settling velocity 



U = u sin t free stream velocity at the outer edge of 



oo o 



the boundary layer 



U critical free stream velocity 



o 7 



U mass-transport velocity 



V, = JL/t speed of particle propagation 



IV 



