Van Mater and Neat 



Early runs on the computer used the cavity dimensions sug- 

 gested in Van Dorn, Le M^haut^, and Hwang [ 1968] and the wave 

 peak-up, wave breaking, decay, and stability criteria which have been 

 outlined previously. To improve agreement between the theory and 

 observation adjustments were made to some of these empirical coef- 

 ficients. First, cavity dimensions were adjusted for the best fit 

 with the results shown below. 



0.3 0.24 



° 'oh Qo h 



'o Oq 



small explosion 7.80 1.53 



moderate explosion 7,82 1.33 



large explosion 8,14 2,03 



recommended by Van Dorn 9.60 2.80 



For wave breaking the peak-up ratio was changed from 1.40 to 

 1,50, breaJcing and decay criteria were not changed. The criteria 

 for stability after breaking was changed as follows 



(§) 



= ^ (o.90 - 0.40 iii^' 



hh ^ g ' 



Stable ° ^ 



where H^ is now taken as the height before peak-up. 



The trajectory of an individual wave ray is dependent on the 

 initial angle at the origin, Gq, bottom profile, and frequency. Con- 

 sequently absolute convergence of a family of wave rays representing 

 an array of frequencies is not possible. To give the best overall 

 conformity over the spatial domain, Qq is adjusted with frequency, 

 i.e. 00 = 9o(co). For the conditions assumed a simple linear varia- 

 tion in eb(co) was found to give a variation in path lengths which 

 generally fell within a 1% band and a variation in offsets from the 

 axis which fell within a 5% band. The control angle upon which 

 60(00) is based is designated 9q . 



With the background now established the following remarks 

 may be made regarding the agreement between the predicted, or to 

 put it more accurately, the hindcast wave system and the wave 

 system observed in experiments, 



(a) For the two smaller explosions, W = 0,139 and W = 0.166, 

 agreement of the envelopes at stations 59 and 64 is very good. The 

 envelopes of the first group are underpredicted at stations 71 and 

 76 but overpredicted at station 100, This infers that the linear 

 theory underpredicts shoaling wave height enhancement in very 



258 



