is basically an acceleration criterion as well. Maximum acceleration can also be 

 written as 



d T T 



(23) 



Thus the acceleration criterion is similar to the velocity criterion with the 

 addition of a scaling by the wave period T. A critical threshold acceleration for 

 harbor operations can be defined from Wilson's slope criterion as 



2ti. 



\d 



2tc. 



^ x (0.0038 ft/sec) 



(24) 



Now the velocity criterion (No. 3) is examined. Maximum velocity in a 

 standing wave (from Equation 21) is 



He .. Hjgd 



= H. 



\d 



(25) 



or, rearranging terms, 



H = u 



(26) 



Putting this expression for H into Wilson's criterion gives 



T N 



< 0.0038 ft/ sec 



(27) 



"„„ < 0.0038 T 



\d 



(28) 



If representative values for T and d are taken, this expression can be evaluated 

 and compared to PIANC's criterion. Assume d=32 ft and 

 from 40 sec to 400 sec. Then 



— = 1, and Tranges 



Chapter 4 Numerical Model 



67 



