(48) 

 Fi = <D >Ts + (c^)Tb - Ti. 

 The stress terms are presented in the form 



T = k|w|w. (49) 



For the surface stress, W is the wind speed at an elevation of 

 10 m cjxjve the water surface. Reid and Bodine (1968) considered k as 

 a function of wind speed in the form 



K = Kn 



(50) 

 (c = «! + K2(l-Wj,/|w|)2 for |w| > Wj, 



where k-^ and /C2 are taken as 1.1 x 10"^ and 2.5 x 10~°, respectively, 

 and Wj, is a critical wind speed which is taken as 7.0 m/s. The 

 coefficient k. is related to the drag coefficient, Cp by the relation 



K = (Pa/P„)CD (51) 



where Pg^ is air density and p^ is water density. 



For large wind speed, k approaches the limiting value of 3.6 x 

 10~^ which corresponds to a drag coefficient of about 3.0 x 10"-^ if 

 the density ratio between air and water is assumed to be 1.2 x 10"^. 

 Equation (50) was used by Wanstrath (1975) in his simulation of storm 

 surge in transformed coordinates while Miyasaki (1963) used a 

 constant 3.2 x 10"^ for « in his computation of storm surge for 

 hurricane Carla. The choice of k for intense winds (Iwl^ 50 m/s) is 



25 



