increases from zero at the free water surface to 

 where pi is approximated as 



Pi = 



1 + 



w H. 



cosh (2TTd/L) 



wd + Pi at the bottom, 



(7-75) 



TTTTTA 



Crest of Clopotis ot Wall 

 ■ho /' 



SWL 



Actuol Pressure 

 Distribution 



Hydrostotic Pressure / 



Distribution 



A 



wd 



XT7777777777 

 P. 



Trough of Clopofis ot Woll 



Figure 7-89. Pressure distributions for nonbreaking waves. 



When the trough is at the wall, pressure increases from zero at the water 

 surface to wd - pi at the bottom. The approximate magnitude of wave force 

 may be found if the pressure is assumed to increase linearly from the free 

 surface to the bottom when either the crest or trough is at the wall. 

 However, this estimate will be conservative by as much as 50 percent for steep 

 waves near the breaking limit. 



Figures 7-90 through 7-95 permit a more accurate determination of forces 

 and moments resulting from a nonbreaking wave at a wall. Figures 7-90 and 

 7-92 show the dimensionless height of the clapotis orbit center above still- 

 water level, dimensionless horizontal force due to the wave, and dimensionless 

 moment about the bottom of the wall (due to the wave) for a reflection 

 coefficient \ = \ . Figures 7-93 through 7-95 represent identical 

 dimensionless parameters for x ~ 0*^ • 



The forces and moments found by using these curves do not include the 

 force and moment due to the hydrostatic pressure at still-water level (see 

 Figure 7-89). 



7-163 



