Table 5. Surf zone similarity parameter versus wave 

 characteristics (after Battjes, 1974b). 



spilling 



col lapsing/ surging 





6-7 2-3 1-2 0-1 



4x10 8x10 



progressive wave 



standing wave 



a>t-nip predominan t 



run-up predominant 



number of waves in surf zone 



Recently, Ostendorf and Madsen (1979) defined a modified Battjes breaker 

 parameter as 



tan3 cosa, (y') 



b 

 -n — 



h = 



(H^/L.) 



for waves of oblique incidence and using the wave height evaluated at break- 

 ing, for convenience. It is then demonstrated that the longshore current 

 theory discussed above, which neglects such surf zone phenomena as wave runup, 

 wave reflection, edge waves and air entrainment but includes a linear y ratio 

 inside the breaker line, is reasonable when 0.3<5,<0.7. The data employed are 

 somewhat different than that used to establish Table 5. Interestingly, they 

 conclude from laboratory data that for y linear in the surf zone, 5v,>0.3, which 

 contradicts the belief, in this opinion, that the theory holds for all spilling- 

 type breakers. 



b. Wave Breaking Criteria . The longshore current models simply take 

 0.5<Y,<1.2 as a breaking criterion. The most common value employed is 0.8 

 (solitary wave theory gives 0.78). The actual MWL, h, = (d+n), » is employed in 

 the ratio (eq. 33). Many other variations are available some including the 

 wave steepness and beach slope in the formulation (e.g., Thornton and Smith, 

 1980 ^; Weishar and Byrne, 1978). Excellent reviews of wave breaking in shal- 

 low water can be found in Collins and Wier (1969), Calvin (1973), Battjes 

 (1974a), and Komar (1976a). 



^^THOPvNTON, E.B. and SMITH, R.M. , "Breaking Wave Criterion on a Sloping Beach," 

 Abstracts, I7th Conference on Coastal Engineering ^ Sydney, Mar. 1980, pp. 

 28-29 (not in bibliography). 



108 



