Figure 1-hl . Definition sketch of wave forces on a vertical cylinder. 



measurements of force, velocity, and acceleration or by measurements of force 

 and water surface profiles, with accelerations and velocities inferred by 

 assuming an appropriate wave theory. 



The following discussion initially assumes that the force coefficients 

 C^ and C^j are known and illustrates the calculation of forces on vertical 

 cylindrical piles subjected to monochromatic waves. A discussion of the 



selection of 



^M 



and 



'D 



follows in Section e. Selection of Hydrodynamic 



Force Coefficients, Cp and C^ . Experimental data are available primarily 

 for the interaction of nonbreaking waves and vertical cylindrical piles. Only 

 general guidelines are given for the calculation of forces on noncircular 

 piles. 



b. Vertical Cylindrical Piles and Nonbreaking Waves; (Basic Concepts) . 

 By analogy to the mechanism by which fluid forces on bodies occur in uni- 

 directional flows, Morison et al. (1950) suggested that the horizontal force 

 per unit length of a vertical cylindrical pile may be expressed by the 

 following (see Fig. 7-67 for definitions): 



X, D M 



2 



ttD du 



— dT + S 2 p ^ "h 



(7-20) 



7-102 



