throughout the text will refer only to grid systems comprised of constant 

 sized, rectangular cells. RCPWAVE is capable of computing solutions on vari- 

 ably sized, rectilinear grid systems. Technology for creating variably sized 

 grids, which are compatible with the wave model, exists at CERC. 



17. Figure 1 shows nine rectangular cells which make up a small part of 

 a larger mesh. Each cell has a length equal to Ax in the x-direction and 

 Ay in the y-direction. The maximum values of i and j are M and N , 

 respectively. 



:_,™„, y-AXIS 













i-1. j-1 



i-1. i 



i-1, i+1 











~T 





U-1 



i.J 



i. i+i 



A* 



* 



i+1, j-1 



i+l.j 



i+1, i+i 









Ay 







V 











AXIS 











Figure 1. Definition of coordinate system and grid cell 

 conventions used in the model 



18. All variables which vary as a function of space are defined at the 

 cell centers. For any dependent variable F , the following finite difference 

 operators are used to approximate certain partial derivatives of F at the 

 position (i,j): 



11 



