and interpolated from the appropriate isolines, respectively. The region to the lower right of 

 the Une of dots indicates the region where use of the hnear theory agrees with the nonUnear 

 results presented within 1 percent in H/L^ and 1" in wave direction, a. 



V. EXAMPLES ILLUSTRATING USE OF WAVE TABLES 

 Introduction 



The preceding chapter has described the formats and the various dimensionless 

 parameters included in the wave tables. To aid in the application of the tables, examples will 

 be presented illustrating their use. The first example is a problem of a near-breaking wave 

 interacting with an offshore structure supported by cylindrical piling. This example will use 

 those tables which contain the wave profile and the wave forces and moments. Additional 

 examples will then be presented which will illustrate the use of most of the remaining wave 

 tables. Where possible, examples were selected to parallel problems which may occur in 

 offshore design. 



It is worthy of note that the tables have a much wider applicability than can be illustrated 

 by the limited number of examples presented here. A thorough familiarity with the 

 information summarized in the tables should aid in an understanding of them and their use 

 in many problems involving water-wave phenomena. The examples will be presented in U.S. 

 Customary units; however the tables are in dimensionless form, and any system could be 

 used readily. 

 Example I-Deck Elevation and Wave Forces and Moments on an Offshore Platform 



Consider the design problem of determining the deck elevation and horizontal wave 

 forces and moments upon individual members of the offshore platform illustrated in 

 Figure 30. Suppose that the design depth (mean low water + maximum tide + storm 

 surge), h, is 41 feet, and the main structural members of the platform and outriggers are 

 pilings 6 feet in diameter, with piling fenders 3 feet in diameter. The fenders extend from 

 4.1 feet above the design Stillwater level to a depth of 8.2 feet. The outriggers are 20.5 feet 

 high. Suppose that analysis indicates that the design wave will have a (breaking) 

 height, H, of 31.78 feet and a period, T, of 20 seconds. The drag and inertia 

 coefficients, C^ and C^, for this structure are assumed to be 1.05 and 1.5, respectively. 



To determine which set of tables to use, calculate h/L^ and H/L^, where L^ = gT^/(27r), 



h 



41 



= 0.02 



Lo 



(5.12) (20)^ 



H 



31.78 



= 0.0155 



Lo 



(5.12) (20)^ 



In this and most subsequent examples in this chapter, the tables for Case 4-D will be used 

 (see Figure 23). A sample table set for Case 4-D is included as Appendix III. 



58 



