552 



INMAN AND BAGNOLD 



Symbols — continued 



[chap. 21 



Symbol 



Dimensions 



Description 



Aj)])lied tangential stress 



Applied tancential stress by the fluid flow only 



Scdiiiiont transport velocity of total load, bed and 



suspended load 



Mean migration velocity of individual grains 



Sediment transport velocity, in to-and-fro motion 



under \\ aves 



Fluid-flow velocity, mean, ui is the longshore 



current velocity 



Wave "orbital velocity" close to bed 



Fluid drift velocity in direction 9 



"Drag velocity" = V(t/p) 



Fall velocity of sediment grains 



Distances in direction of flow or travel 



Distances normal to bed svirface 



Angle between wave orthogonal (ray) and a normal 



to the beach ; angle between wave crest and bottom 



contour (Fig. lib) 



Angle of inclination of bed surface to horizontal 



Relative wave height, H/h 



Efficiency of bed -load, suspended load transport 



Whole height (crest to trough) of a sand ripple 



The stress ratio, rt/ips — p)9D 



Direction in horizontal plane 



von Karman constant 



Kinematic viscosity 



Density of fluid 



Effective density of sediment grains, dry bulk density 



of sand 



Fluid shear stress 



Fluid shear stress exerted at bed boundary 



Threshold value of to 



Angle of solid friction, tan 0= T/P 



Available power attributable to unit boundary area. 



In the case of waves, a» is the decrement dP/dx of the 



transmitted power attributable to bed drag 



References 



Bagnold, R. A., 193(). The movement of desert sand. Proc. Roy. Soc. London, A157, 



594-620. 

 Bagnold, R. ,\.. 1940. Beach formation by waves; some model -experiments in a wave 



tank. ,/. Inst. Civ. Eng., Paper 5237, 27-52. 

 Bagnold, R. A., 1946. Motion of waves in shallow watei-. Interaction between waves and 



sand bottoms. Proc. Roy. Soc. London. A187, 1-18. 

 Bagnold, R. A., 1947. Sand movement by waA-es : some small-scale experiments with sand 



of very low density. J. Inst. Civ. Eng., Paper 5554, 447-469. 

 Bagnold, R. A., 1954. Experiments on a gravity-free dispersion of large solid spheres in a 



Newtonian fluid under shear. Proc. Roy. Soc. London, A225, 49-63. 



