Figure 9. Track of Hurricane Donna 



42. With the boundary and initial conditions for a storm simulation 



specified by tides, the meteorological fortes appear in the computations as 



the terms F , F , and n in Equations 2 and 3. These terms represent the 

 X y a ^ '^ 



shear (wind stress) and normal (barometric pressure differential) forces 

 applied to the water surface during the storm. WIFM obtains values for the 

 wind and pressure fields from datasets created by other computer codes, such 

 as the SPH Program. Wind velocity and pressure head values for every grid 

 cell are read into WIFM every few time-steps, and then WIFM converts the wind 

 velocity into surface shear stress by Charnock's linear relation (Garrett 

 1977). The drag coefficient for Charnock's method is: 



28 



