63. Svendsen (1984, 1985) determined F from crude approximations of 

 actual flow in surf zone waves. Svendsen used a nondimensional form of the 

 energy flux B where 



B = 



pgCH 



(41) 



and C is wave celerity, equal to L/T , where L is wavelength. Svendsen 

 assumed an idealized flow within the wave and the so-called surface roller, 

 and he approximated B by 



T 2 



n 



1 A = 



dt + 



2 H 2 



(42) 



in which r? is the free -surface water elevation, and A s is the cross- 

 sectional area of the surface roller. The surface roller is defined as the 

 recirculating part of the flow resting on the front face of the broken wave. 

 Svendsen found a relationship for A s based on experimental data of Duncan 

 (1981) where 



A c = 0.9H 2 



(43) 



This reduces Equation 42 to 



B = 



1 

 H 2 



dt + 0.45 



(44) 



64. Dally (1980) and Dally, Dean, and Dalrymple (1985a, 1985b) derived 

 an equation to calculate the decay of broken waves, in which e was assumed 

 to be proportional to the difference between local energy flux F and a 

 stable energy flux F s : 



37 



